【摘要】 快堆用钠冷却剂中锂的含量对堆的核性能有较大影响,为了检测核级钠中锂的含量,建立了真空蒸馏-石墨炉原子吸收光谱法测定金属钠中微量锂的方法。在氩气氛下取4.0g左右钠于钽坩埚中,在360℃及0.01Pa真空度下蒸馏除钠,残渣用硝酸（1:2）溶解后,在671.0nm波长处,用石墨炉原子吸收光谱法测定锂。实验中对蒸馏条件、石墨炉原子吸收测试条件及来自于基体钠、酸及共存元素的干扰等进行了一系列研究,用氯化锂和硝酸锂做加钠回收实验,回收率分别为96.8％及97.4％,相对标准偏差小于5％。该方法满足了核级钠中杂质锂(<1×10^-5)的质量监测要求,达到了国际上同类分析方法的水平,已用于国产工业钠原料和净化后的高纯钠中锂含量的分析。更多还原

【Abstract】 When sodium is used as a coolant in China Experimental Fast Reactor, the lithium content in sodium has an effect on the nuclear property of reactor. A method has been developed to determine the trace lithium in sodium metal at the level of less than ten parts per million. About 0. 4 g sodium is placed into a high-purity tantalum crucible, then it is placed in a stainless-steel still to distill at 360C under vacuum (0. 01 Pa). After the sodium has been removed, the residue is dissolved by nitric acid (1 : 2) and analyzed with Graphite Furnace Atomic Absorption Spectroscopy at 671. 0 nm wavelength. The distillation conditions, working conditions of the instrument and interferences from matrix sodium, acid and concomitant elements have been studied. Standard addition experiments are carried out with lithium chloride and lithium nitrate. The percentage recoveries are 96.8% and 97. 4% respectively. The relative standard deviation is less than +5%. The method has been used to determine lithium content in high pure sodium and industrial grade sodium.更多还原