Hot test of partitioning strontium from high-level liquid waste (HLLW) by dicyclohexano-18crown-6 (DCH18C6)

The crown ether strontium extraction(CESE) process for partitioning strontium from HLLW was studied. A hot test was carried out in a counter current mode with genuine HLLW by using a miniature centrifugal contactor set. 0.1 mol/L DCH18C6 in 1-octanol was used as extractant. The feed solution was the HLLW raffinate of TRPO process after removing TRU elements. Acidity of the feed was 1.45 mol/L HNO3. In the hot test 10 extraction stages and 2 scrubbing stages were used in the extraction section. Four stripping stages were used in the backextraction section. The results of the hot test were very attractive. More than 99.96% of strontium were extracted from the feed solution and above 99.84% strontium was stripped out of the organic phase. Non of the TRU elements was extracted with strontium by the extractant. Only about 0.4% of Cs were extracted and found in the Sr stripping stream. The hot test result proved that the CESE process was a promising process to remove strontium from HLLW.