Extraction of lead and strontium from hazardous waste streams by solvent extraction with 4',4',(5')-di-(T-butyldicyclohexo)-18-crown-6

Extraction of Pb from nitric acid solutions and simulated acidic hazardous waste streams has been demonstrated with 0.15 M 4',4',(5')-di-(t-butyldicyclohexo) 18-crown-6 and 1.2 M tributyl phosphate in a commercial isoparaffinic hydrocarbon called Isopar L(.). The extraction has been shown to be dependent upon extractant concentration, aqueous nitrate concentration, and the identity of the predominant anion in the aqueous phase. It has been shown that Pb and Sr can be extracted simultaneously and stripped efficiently from the loaded organic phase. The quantitative (> 99 %) removal of Pb and Sr can be achieved in 3 to 4 batch contact extractions. Batch contact flowsheets have been utilized to demonstrate the potential for the simultaneous removal of Sr and Pb from simulated radioactive waste followed by partitioning of the extracted Sr fraction from the Pb fraction.