二氧化铀芯块中微量Mn、Cr、Ni、Mo、Th的测定方法改进

Improve of Determination of Mn, Cr, Ni, Mo and Th in Uranium Dioxide Pallets

摘要: 硝酸溶解二氧化铀芯块，采用TBP树脂连续分离Mn、Cr、Ni、Mo、Th五种元素，等离子体发射光谱（ICP-OES）法测定Mn、Cr、Th，石墨炉原子吸收（GAAS）法测定Ni、Mo。结果表明：3 mol/L硝酸介质中，U、Th被TBP树脂吸附，Mn、Cr、Ni、Mo 4种元素直接进入接收液（A），继续用6 mol/L盐酸平衡柱子，弃去8 mL死体积后，此时Th淋洗进入接收液（B）。接收液为高酸基体，元素浓度低，故将接收液蒸至近干，稀酸溶解测定。采用标准物质（GBW04242）对该方法进行验证，测定值均在标准值的置信区间内。

Abstract: Uranium dioxide pallets were dissolved in HNO₃. Mn, Cr, Th were determined by ICP-OES and Ni, Mo by GAAS after separation by TBP resins. U and Th were adsorbed in 3 mol/L HNO₃ by TBP resins and Mn, Ni, Mo, Cr were received as solution A. Th was received as solution B after 8 mL dead volume. Solution A and B were steamed to nearly dry and then dissolve by dilute acid for measurement. The method is verified through reference material GBW04242. The measured values are in the confidence interval.