Management of spent solvents by alkaline hydrolysis process

This paper deals with the treatment method for the management of spent solv ents of reprocessing origin (30% tri-n-butyl phosphate in n-dodecane) using the 'alkaline hydrolysis process'. The consolidated work reported herein h as established total conversion of TBP to aqueous soluble reaction products and transfer of near total radioactivity associated with the waste into th is aqueous phase. It was also observed that n-dodecane (diluent) did not ta ke part in the reaction and separated out as the top layer. Repeated runs h ave established the process on engineering scale (up to 200 1/batch) with r egard to conversion of TBP into sodium salt of HDBP, butanol and recovery o f the diluent practically free of TBP. The measured parameters, specificall y, temperature and pressure did not deviate from set limits during the enti re reaction time indicating safe operation. Experiments were also carried o ut on immobilization of the aqueous phase resulting from hydrolysis which c ontains almost all the radioactivity associated with the original spent sol vent. These immobilization studies have established compatibility of the pr ocess generated aqueous stream with cementitious matrix. (C) 1999 Elsevier Science Ltd. All rights reserved.