X射线荧光光谱无标定量测定稀土矿石中五氧化二磷

Determination of phosphorus pentoxide in rare earth ore by X-ray fluorescence spectrometry coupled with standard-less quantitative analysis

利用粉末压片法制备样品,通过在Omnian无标定量分析软件中添加与待测组分相似样品来建立标签,可校正粉末样品可能存在的矿物效应、颗粒效应及制样引进的误差,从而实现X射线荧光光谱法(XRF)对稀土矿物中P2O5的准确测定。通过试验确定了压片制样的最佳制样条件为:样品粒度小于0.074mm、压力为40t、称样量为6.00g和保压时间为30s。对含不同梯度含量P2O5的稀土矿石进行正确度考察,发现以Omnian软件未添加标签而直接测定的P2O5结果差值较大,而Omnian添加标签的分析结果与国家标准方法的分析结果基本吻合;精密度试验表明,P2O5测定结果的相对标准偏差(RSD,n=8)小于3%。无需大量的标样建立校准曲线,能满足稀土矿石含磷量的精确分析要求。

The sample was prepared by pressed powder pellet method.The tag was established by adding the standard sample with similar components into Omnian standard-less quantitative analysis software.Thus,the errors caused by possible mineral effect,particle effect and sample preparation could be corrected for powdered samples.The accurate determination of P2O5 content in rare earth ores by X-ray fluorescence spectrometry（XRF）was achieved.The optimal sample preparation conditions were obtained by experiments：the particle size was less than 0.074mm;the pressing pressure was 40t;the sample mass was6.00 g and the holding time was 30 s.The accuracy test was investigated using rare earth ore containing different content gradients of P2O5.It was found that the direct determination results of P2O5 by Omnian software without addition of tag showed large errors.After adding tag,the analytical results by Omnian were basically consistent with those obtained by national standard method.The precision test indicated that the relative standard deviation（RSD,n=8）of determination results for P2O5 was less than 3%.The proposed method could meet the accurate analysis requirements of P2O5 in rare earth ores without the establishment of standard curve using large amounts of standard samples.