Removing Acetic Acid from a UREX+ Waste Stream: A Review of Technologies

This study explores different technologies for removing acetic acid from a UREX+ waste stream. The waste stream contains both nitric and acetic acids, and the acetic acid must be removed from the waste stream to prevent potential problems in the downstream steps as well as affecting the recycle of nitric acid. The acetic acid is formed after the UREX step of the process as a result of hydrolytic degradation of acetohydroxamic acid used to suppress plutonium extraction. Of the available technologies, the two most attractive approaches are solvent extraction and distillation. In industry, solvent extraction is used for more dilute concentrations of acetic acid while distillation is used for concentrated acetic acid. If a liquid-liquid extraction is viable, this would be the best option with the addition of an extractant, like tributyl phosphate or tri-n-octyl amine, if needed. However, if acetic acid removal can be delayed until the end of the UREX+ process when the nitric acid may be concentrated for recycle, distillation may remain an option, though not necessarily a better option than solvent extraction.