电感耦合等离子体质谱法测定离子型稀土矿中离子相稀土总量及分量

采用硫酸铵溶液提取离子型稀土原矿试样中离子相稀土,以硫酸铵溶液为基体配制校准系列溶液,建立了电感耦合等离子体质谱法(ICP-MS)测定样品溶液中离子相稀土总量及分量的方法。实验表明:对于10.00 g离子型稀土矿试样,加入100 mL 50 g/L硫酸铵溶液振荡15 min后放置30 min可有效提取出离子相稀土;采用5.0 g/L硫酸铵溶液进行校准系列溶液的基体匹配,选择¹⁰³Rh-¹⁸⁵Re双内标可有效校正硫酸铵的基体效应及仪器信号的漂移影响;选择合适的同位素消除了可能存在的质谱干扰。在最佳条件下进行测定,15个稀土元素的校准曲线在10.0~100.0 μg/L范围内线性相关系数均大于0.999 91,方法检出限在0.10~0.66 μg/g之间。方法应用于不同离子型稀土矿区中离子相稀土总量及分量的测定,结果与电感耦合等离子体原子发射光谱法(ICP-AES)一致,相对标准偏差(RSD,n=11)在1.0%~5.2%之间,回收率在98%~104%之间。

Determination of total ionic-phase rare earth and component inion-adsorption rare earth ore by inductively coupled plasma mass spectrometry

The ionic-phase rare earth in raw ores of ion-adsorption rare earth was extracted by ammonium sulfate and the calibration solution series were prepared with ammonium sulfate solution as matrix. Thus, a method for the determination of total ionic-phase rare earth and component in the sample solution was established by inductively coupled plasma mass spectrometry(ICP-MS). It showed that ionic-phase rare earth could be effectively extracted from 10.00 g of ion-adsorption rare earth ore samples which had been concussed for 15 min with 100 mL of 50 g/L ammonium sulfate solution added and kept still for 30 min; 5.0 g/L ammonium sulfate solution was used for matrix matching of calibration solution series, while ¹⁰³Rh-¹⁸⁵Re double inner standard method was used to calibrate the matrix effect of ammonium sulfate and the signal shift effect of instrument; the possible mass spectral interference was eliminated with appropriate isotopes. Under optimal conditions, the linear correlation coefficient of the calibration curve of fifteen rare earth elements within 10.0-100.0 μg/L were all larger than 0.999 91. The detection limit was 0.10-0.66 μg/g. When the method was employed to determine total ionic-phase rare earth and component in different ion-adsorption rare earth ore zones, the results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES). The relative standard deviation (RSD, n=11) was in the range of 1.0%-5.2 %, and the recovery was between 98% and 104%.