熔融制样X射线荧光光谱法测定锑矿石中的锑和14种微量元素

摘要

锑矿石分析通常分别采用酸分解系统和碱熔系统，萃取分离后应用容量法、原子吸收光谱法、原子荧光光谱法等分析手段进行单项测定，样品处理繁琐、操作复杂，分析过程常因熔矿不完全而导致结果偏低或失真，难以满足地质测试的需要。本文建立了玻璃熔融制样，波长色散X射线荧光光谱测定锑矿石中的锑及14种次量元素与伴生元素（Cu、Pb、Zn、As、Co、Ni、W、Ba、S、SiO2、Al2 O3、TFe、CaO、MgO）的快速分析方法。用国家标准物质和人工合成标准参考物质拟合校准曲线，对熔融条件进行了研究。确定样品与四硼酸锂－偏硼酸锂－氟化锂复合熔剂的熔融稀释比例为1∶20，以硝酸铵为氧化剂，碳酸锂为保护剂，700℃预氧化，在1050℃温度下熔融完全，有效地防止了As、S的挥发损失，解决了化学法测试样品处理复杂、不能同时测定多元素、测试元素偏少的问题。一些元素的检出限为Sb 0．14％，Cu 0．0027％，Pb 0．0025％，Zn 0．0046％，As 0．0028％，S 0．021％；方法精密度（RSD，n＝12）小于5％；选用合成标准物质和实际生产锑矿石试样进行验证，测定结果与参考值或化学值一致性良好。本法大部分元素检出限都要稍高于粉末压片法，但操作简单，测试范围更宽，适用于实验室对不同锑矿矿种批量样品中多元素快速、准确检测的需要。%The analysis of antimony ores usually uses acid decomposition and an alkali fusion system,each component is seperated with solvent extraction and then determined by various analytical methods such as volumetric method,Atomic Absorption Spectrometry and Atomic Fluorescence Spectrometry.These methods not only have complicated operations with long time consuming,but also obtain low value or become distorted due to incomplete digestion or serious interferences,which subsequently make it difficult to meet the needs of geological analysis.The glass fusion preparation technique and establishing the rapid analysis method by using wavelength dispersion X-ray Fluorescence Spectrometry (XRF)are discussed and presented in this paper to determine antimony and 1 4 kinds of trace and associated elements (Cu,Pb,Zn,As,Co,Ni,W,Ba,S,SiO2,Al2O3,TFe,CaO and MgO)in antimony ores.The calibration cure was calibrated by using the national standard material and synthetic standard reference material,in order to study melting conditions.The sample and lithium teraborate-lithium metaborate-lithium fluoride were melted with dilution ratio of 1 ∶20 with ammonium nitrate as oxidant and lithium carbonate as protective agent.The sample was preoxidated at 700℃,and was completely melted at 1 050℃,which effectively prevented the volatilization of As and S to solve the problems of complex procedure,the inability to simultaneous determine elements and insufficient test elements by chemical method.The detection limits of method are lower than previous methods (Sb:0.1 4%,Cu:0.0027%,Pb:0.0025%,Zn:0.0046%,As:0.0028% and S:0. 021%)and the precision (RSD,n=1 2)is lower than 5%.Verified by synthetic standard material and the actual production of an antimony ore sample,the results show good consistency with the reference values obtained by the chemical method.Although the detection limits are higher than those for the powder pellet method,the operation of this method was simple,rapid and accurate,making it applicable to laboratory analysis requirements of varied and batch antimony ores samples.