熔融制样-X射线荧光光谱法测定电气石中12种主次量元素

摘要

电气石是一类含硼的铝硅酸盐矿物,化学成分复杂、化学稳定性强,不易湿法分解,B2O3含量较高,导致其主次量元素的同时测定存在一定困难.本文采用熔融法制样,建立了X射线荧光光谱法测定电气石Na2O、MgO、Al2O3、SiO2、P2O5、K2O、CaO、TiO2、V2O5、Cr2O3、MnO、TFe2O3等主次量元素的分析方法.样品与四硼酸锂-偏硼酸锂-氟化锂(质量比为4.5 :1 :0.4)混合熔剂的稀释比例为1 :10,消除了粒度效应和矿物效应;在缺少电气石标准物质的情况下,选择土壤、水系沉积物及多种类型的地质标准物质绘制校准曲线,利用含量与电气石类似的标准物质验证准确度,测定结果的相对标准偏差小于4.2%.采用所建方法测定四种不同类型电气石实际样品,测定值与经典化学法基本吻合.本方法解决了电气石不易湿法分解和硼的干扰问题,测定结果准确可靠,与其他方法相比操作简便,分析周期短.%Tourmaline is a class of boron-bearing aluminosilicate minerals.It has a complex chemical component and stable chemical property,and is difficult to decompose by wet methods.The high content of B2O3makes it difficult to simultaneously determine major and minor elements in tourmaline.X-ray Fluorescence Spectrometry (XRF)was applied to determine Na2O,MgO,Al2O3,SiO2,P2O5,K2O,CaO,TiO2,V2O5,Cr2O,MnO, TFe2O3in tourmaline samples with fusion sample preparation in this study.The dilution ratio of 1 :10 was set for the sample to flux lithium tetraborate-lithium metaborate-lithium fluoride(quality ratio of 4.5:1:0.4)in order to eliminate the particle size effect and mineral effect.When the tourmaline reference materials were unavailable, soil,stream sediment and different types of rock reference materials were used to establish calibration curves.The accuracy of the method was verified using reference materials that have chemical compositions similar to tourmaline. The relative standard deviation(RSD,n=1 1)was less than 4.2%.The proposed method was used to determine four different tourmaline samples,the results were in good agreement with the values obtained by wet chemical methods.This method solved the problem that tourmaline is difficult to decompose and eliminated the interference effect of boron.The analytical results are accurate and reliable.Compared with other methods,this method is easy to operate and has a short analytical time.