X射线荧光光谱法测定稀土精矿中的稀土元素分量

氟碳铈矿、独居石、磷钇矿和风化壳淋积型稀土矿四种稀土精矿样品采用化学法预分离富集,X射线荧光光谱法测定样品中稀土元素和伴生的铀、钍元素含量,选择以硼酸盐为主的混合熔剂高温熔融制样,消除矿物间存在的矿物结构影响,通过加大熔剂稀释比降低元素间的基体效应,人工标准样品绘制标准曲线,用数学校正方法校正元素间的谱线重叠效应。对淋积型稀土矿样品重复测定12次,方法检出限为0.9~42.1 μg/g,待测组分的相对标准偏差(RSD)均小于10%,测定结果与电感耦合等离子体质谱法的测定值基本吻合。此方法应用于国家一级标准物质稀土标准样品定值工作,检出限和精密度能够满足分析要求,报出数据被采用率达到100%。

Determination of Rare Earth Elements in Rare Earth Ore Concentrates by X-ray Fluorescence Spectrometry

A chemical method was used for the preparation and enrichment of four rare earth concentrates(bastnaesit,monazite,xenotime and weathering crust Elution-deposited rare earth ore).Mixed flux,mainly consisting of borate,was applied to eliminate the presence of the structure of minerals with high temperature fusion.Increasing the flux dilution ratio reduces the matrix effects between elements.The calibration curve was established by artificial standard materials and the overlap effect between spectral lines was corrected by mathematical method.Compared with data by Inductively Coupled Plasma-Mass Spectrometry(ICP-MS),the contents of rare earth elements and uranium and thorium were determined by X-ray Fluorescence Spectrometry(XRF).The REE-3 sample was measured 12 times and the detection limit was 0.9-42.1 μg/g.The relative standard deviations(RSD) for all components were less than 10%.Applied to national standard reference materials of rare earth elements,all the data by this method were in agreement with those by other analytical methods,within detection limits and precision.All reported data were adopted.