电感耦合等离子体质谱法测定离子吸附型稀土矿中全相稀土总量

采用硝酸-氢氟酸-高氯酸混酸溶解试样,以电感耦合等离子体质谱法(ICP-MS)对试样溶解液进行测定,提出了以ICP-MS测定离子吸附型稀土矿中全相稀土总量的方法。对氢氟酸用量和测定液中硝酸的含量进行了考察,最终确定氢氟酸用量为5.0mL,测定液介质为体积分数为2%的硝酸。在优化的仪器条件下,15种单一稀土元素校准曲线的线性相关系数均大于0.9999,方法检出限为2.4μg/g。采用实验方法对稀土矿石国家标准物质GBW07158、GBW07160、GBW07161(用于标样制定的样品均采自江西省龙南离子吸附型稀土矿区)中的稀土总量进行测定,测定结果与认定值基本一致。将实验方法应用于稀土矿石国家标准物质GBW07159、GBW07160与离子吸附型稀土矿实际试样中稀土总量的测定,测得结果的相对标准偏差(RSD,n=11)为1.7%~3.1%。

Determination of total-phase rare earth content in ion-adsorption rare earth ore by inductively coupled plasma mass spectrometry

After the sample was dissolved with nitric acid-hydrofluoric acid-perchloric acid mixture, the sample solution was determined by inductively coupled plasma mass spectrometry (ICP-MS). Consequently, a determination method of total-phase rare earth content in ion-adsorption rare earth ore by ICP-MS was proposed. The dosage of hydrofluoric acid and the content of nitric acid in determination solution were investigated. Finally, 5.0mL of hydrofluoric acid was selected and 2% (volume fraction) nitric acid was used as determination medium. Under the optimized instrumental conditions, the linear correlation coefficients of calibration curves for 15 rare earth elements were all higher than 0.9999. The detection limit was 2.4μg/g. The contents of total-phase rare earth in national certified reference materials (CRMs) of rare earth ore including GBW07158, GBW07160 and GBW07161 (the samples for CRMs formulation were all from Longnan ion-adsorption rare earth ore region in Jiangxi Province) were determined according to the experimental method, and the results were basically consistent with the certified values. The proposed method was applied for determination of total-phase rare earth content in national certified reference materials of rare earth ore (GBW07159 and GBW07160) and actual ion-adsorption rare earth ore samples. The relative standard deviations (RSD, n=11) for the results were between 1.7% and 3.1%.