Fission Product Extraction (FPEX);Development of a Novel Solvent for the Simultaneous Separation of Strontium and Cesium from Acidic Solutions

摘要

A synergistic extraction solvent for the simultaneous removal of cesium and strontium from acidic solutions has been investigated.The extraction solvent consists of,4,4',(5')-di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6),calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6),and 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB modifier) in a branched aliphatic kerosene (Isopar~R L).Extraction synergy for strontium was observed when DtBuCH18C6 was combined with the BOBCalixC6 cesium extractant solvent and Cs-7SB modifier or if the Cs-7SB modifier was substituted into the SREX (Strontium Extraction) solvent in place of TBP.The novel process extracted both cesium and strontium simultaneously from 1 M nitric acid solutions with distribution ratios of 8.8 and 7.7 for strontium and cesium,respectively,at ambient temperature.Distribution coefficients for cesium and strontium as a function of nitric acid concentration and temperature were also obtained with 0.5 M < [HNO_3] < 2.5 M giving favorable distribution ratios.This new process utilizing the combined solvent has been named the Fission Product Extraction Process (FPEX).