电感耦合等离子体原子发射光谱法测定电池级混合稀土金属中稀土配分和非稀土杂质

盐酸溶解样品后,将稀土配分镧、铈、镨、钕和非稀土杂质铁、硅、锌、镁配制成混合标准溶液系列并绘制校准曲线,保持标准溶液系列中稀土总量与试液中稀土总量一致以消除基体效应,采用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定电池级混合稀土金属中稀土配分镧、铈、镨、钕和非稀土杂质铁、硅、锌、镁。进行了各元素分析谱线的选择,考察了稀土元素对非稀土杂质元素及非稀土杂质元素间的干扰情况。各元素校准曲线线性回归方程的相关系数均不小于0.998 8。按照实验方法测定合成样品中稀土配分镧、铈、镨、钕,测定结果与理论值一致,结果的相对标准偏差(RSD,n=11)不大于3.0%。非稀土杂质铁、硅、锌、镁的检出限为0.001 0%～0.002 8%(质量分数),测定下限为0.005 0%～0.014%(质量分数)。对低锌低镁电池极混合稀土金属样品中非稀土杂质进行测定,测定值与参考值一致,测定结果的相对标准偏差(RSD,n=11)为1.3%～9.0%。按照实验方法测定实际电池级混合稀土金属样品和富镧金属样品中稀土配分镧、铈、镨、钕和非稀土杂质铁、硅、锌、镁,测定值与其他分析方法的结果基本一致。

Determination of rare earth distribution and non-rare earth impurities in battery grade mischmetal by inductively coupled plasma atomic emission spectrometry

The sample was dissolved with hydrochloric acid. The mixed standard solution series were prepared with the rare earth distribution(lanthanum, cerium, praseodymium and neodymium) and non-rare earth impurities (iron, silicon, zinc and magnesium) to draw the calibration curves. The total content of rare earth elements in standard solution series was consistent with those in sample solution to eliminate the matrix effect. The rare earth distribution (lanthanum, cerium, praseodymium and neodymium) and non-rare earth impurities (iron, silicon, zinc and magnesium) in battery grade mischmetal were simultaneously determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The analytical lines for testing elements were selected. The interference of rare earth elements to the non-rare earth impurities as well as the mutual interference among non-rare earth impurities was investigated. The correlation coefficients (r) of linear regression equations of calibration curves were higher than 0.998 8. The rare earth distribution including lanthanum, cerium, praseodymium and neodymium in synthetic sample were determined according to the experimental method. The found results were consistent with the theoretical values, and the relative standard deviations (RSD, n=11) were not more than 3.0%. The detection limit of non-rare earth impurities including iron, silicon, zinc and magnesium was between 0.001 0% and 0.002 8% (mass fraction). The low limit of determination was between 0.005 0% and 0.014% (mass fraction). The non-rare earth impurities in low-zinc low-magnesium battery grade mischmetal sample were determined, and the found results were consistent with the reference values. The RSD (n=11) was between 1.3% and 9.0%. The rare earth distribution (lanthanum, cerium, praseodymium and neodymium) and non-rare earth impurities (iron, silicon, zinc and magnesium) in actual battery grade mischmetal samples and lanthanum-rich metal samples were determined according to the experimental method, and the found results were basically consistent with those obtained by other analysis methods.