分光光度法测定高放废液中的稀土总量  

Determination of Total Rare Earth in HLLW by Spectrophotometry

作　　者：夏峰林 孔雪艳 史秀梅 XIA Feng-lin;KONG Xue-yan;SHI Xiu-mei(The 2nd Branch of the 404 Ltd.,China National Nuclear Corporation,Lanzhou 732850,China)

机构地区：[1]中核四0四有限公司第二分公司,甘肃兰州732850

出　　处：《核化学与放射化学》2020年第5期371-377,I0004,共8页Journal of Nuclear and Radiochemistry

摘　　要：采用冠醚-杯冠-正辛醇萃取剂在适宜酸度条件下萃取高放废液中的锶、铯,萃余水相调节酸度后,用三正辛基氧化磷(TOPO)-环己烷将铀、钚、钍等萃入有机相,萃余水相在一定酸度条件下,可以采用偶氮氯膦mA与稀土元素直接显色,进而采用分光光度法测定其稀土总量。对冠醚-杯冠-正辛醇萃取剂萃取高放废液中的90 Sr和137 Cs进行了条件实验,确定了TOPO萃取不影响稀土元素测定的实验条件,对偶氮氯膦mA显色测定稀土元素的显色条件进行了研究,最终建立了此分析方法。结果表明,在4.5 mol/L硝酸体系中,冠醚-杯冠-正辛醇萃取剂可以萃取高放废液中的90 Sr和137 Cs,而不影响稀土元素的测定。在0~10 mg/L范围、670 nm处,偶氮氯膦mA与稀土元素显色,吸光度与稀土元素的质量呈线性关系。采用此方法测定模拟高放废液中总稀土含量,相对标准偏差为2.3%(n=6),重加回收率为89.9%~97.7%;真实高放废液中稀土元素总量测定的相对标准偏差为6.3%(n=3)。In this paper,90 Sr and 137 Cs were extracted into the organic phase from high level liquid waste(HLLW)by crown ether-calixarene crown ether in suitable acidic conditions.Then,U,Pu,Th,etc.were also extracted into the organic phase by TOPO-cyclohexane.The water phase was colored by chlorophosphonazo mA in suitable conditions in order to obtain the content of RE in HLLW.The extraction conditions of 90 Sr and 137 Cs by crown ether-calixarene crown ether and that of TOPO-cyclohexane were investigated.The coloring conditions of chlorophosphonazo mA were studied and determined.The results show that 90 Sr and 137 Cs are extracted into the organic phase from HLLW by crown ether-calixarene crown ether in 4.5 mol/L HNO 3,while RE are not extracted.The absorbance is linear with the quality of RE during the 0-10 mg/L at 670 nm.The relative standard deviation of RE in the simulated-HLLW is 2.3%(n=6),and the recovery rate is 89.9%-97.7%,while,the relative standard deviation of RE in real HLLW is 6.3%(n=3)using this method.

关 键 词：分光光度法 高放废液 稀土 偶氮氯膦MA 

分 类 号：TL241.1[核科学技术—核燃料循环与材料] O657.32[理学—分析化学]