电感耦合等离子体原子发射光谱法测定铀矿石中全铁

采用分步酸溶的方法,先以H₂SO₄-HClO₄-HF溶解样品,再以HNO₃作为复溶酸,最后用HCl(1+3)作为介质酸,选择Fe 259.94 nm为分析谱线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铀矿石中全铁。铁的质量浓度在14～224 μg/mL范围内,校准曲线的线性相关系数r=0.999 9。全铁的检出限为1.25×10^-4%。采用实验方法测定6个国家产铀岩石标准物质GBW04117～GBW04122中全铁,结果的相对标准偏差(RSD,n=20)为1.2%～3.6%,测定结果与认定值相符;用于10种铀矿石实际样品中全铁的测定,结果与采用核工业标准方法EJ/T 297.3-1987的测定结果相吻合。按照实验方法和EJ/T 297.3-1987测定标准物质中全铁,对两种方法的测定值进行比较,通过F检验和t值检验,表明实验方法与标准方法EJ/T 297.3-1987无显著性差异。

Determination of total iron in uranium ore by inductively coupled plasma atomic emission spectrometry

The step-by-step acid dissolution method was adopted. The sample was firstly dissolved with H₂SO₄-HClO₄-HF; then, HNO₃ was used as redissolution acid; finally, HCl(1+3) was used as medium acid. Fe 259.94 nm was selected as the analytical line. The content of total iron in uranium ore was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). When the mass concentration of iron was in range of 14-224 μg/mL, the linear correlation coefficient of calibration curve was r=0.999 9. The detection limit of total iron was 1.25×10^-4%. The proposed method was applied to the determination of total iron in six national certified reference materials of uranium ore, including GBW04117-GBW04122. The relative standard deviations (RSD, n=20) were between 1.2% and 3.6%, and the found results were consistent with the certified values. The content of total iron in ten actual uranium ore samples was also determined according to the experimental method, and the found results were consistent with those obtained by EJ/T 297.3-1987. The total iron in certified reference materials was determined according to the experimental method and EJ/T 297.3-1987. The determination results of two methods were compared. The F test and t rest indicated that the proposed method and EJ/T 297.3-1987 had no significant difference.