Separation of Americium from Lanthanides by Purified Cyanex 301 Countercurrent Extraction in Miniature Centrifugal Contactors

摘要

In order to further test the actinides/lanthanides separation performance by Cyanex 301 extraction, a countercurrent extraction experiment was carried out in the present work. The separation process consisted of 7-stage extraction, 3-stage scrubbing and 4-stage stripping. 14 miniature centrifugal contactors were installed in glove box for the experiment. The feed solution from TRPO process, mainly consisting of 4.4M HNO_3,~3.7×108Bq Am~(-2)41, 0.02M lanthanides,~120ppm Mo and 100ppm Fe, was pretreated by the following procedures: denitrating to 0.2M HNO_3 by formic acid, adjusting pH to 2 by 8M NaOH, removing most Fe~(3+) by 0.2M Cyanex 301-kerosene cross-flow extraction, and then adjusting pH to 3.5 by 1M NaOH. About 5.6×108Bq Pm-147 was added into the feed solution to trace lanthanides during the experiment. The experiment lasted for 9 hours with a feed flow rate of 30ml/h. The results show that 99.95% Am was separated from lanthanides and only 0.1% lanthanides were extracted together with Am. 99.3% Am and 96.6% Pm were stripped from load Cyanex 301 by 1.0M HNO_3, respectively.