熔融制样-X射线荧光光谱法测定锑矿石中主次成分

锑的准确含量是锑矿石贸易结汇的重要依据,准确测量锑矿中锑及其他元素的含量,对于矿产综合评价和综合利用十分重要。采用四硼酸锂和偏硼酸锂混合熔剂(m∶m=67∶33)在1 050 ℃熔融制样,以0.20 mL 60 mg/mL LiBr溶液为脱模剂,实现了波长色散X射线荧光光谱法对锑矿石中Sb₂O₃、Al₂O₃、SiO₂、CaO、TiO₂、MnO、MgO、Fe₂O₃、Cu、Zn、Na₂O、K₂O等12个组分的同时测定。采用低温硝酸锂预氧化处理样品,解决了硫含量较高的硫化锑矿样品对铂-金合金坩埚的腐蚀问题。以8个锑矿石有证参考物质及以有证参考物质为基体合成的校准样品绘制校准曲线,可满足各组分的定量检测要求。此外,实验采用理论α系数法校正了基体效应。精密度考察发现,锑矿石样品各组分测定结果的相对标准偏差(RSD,n=12)在0.1%～9.7%之间。对有证参考物质及合成样品进行准确度验证,分析结果与认定值或参考值一致。

Determination of major and minor components in antimony ore by X-ray fluorescence spectrometry with fusion sample preparation

Accurate content of antimony was an important index to the trade settlement of antimony ore, so the accurate determination of antimony and other elements in antimony ore was pretty important to mineral comprehensive evaluation and utilization. Mixed reagent of Li₂B₄O₇ and LiBO₂ (m∶m=67∶33) was used for sample fusion at 1 050 ℃ and 0.20 mL of 60 mg/mL LiBr solution was used as release agent. Thus, simultaneous determination of twelve components such as Sb₂O₃, Al₂O₃, SiO₂, CaO, TiO₂, MnO, MgO, Fe₂O₃, Cu, Zn, Na₂O and K₂O in antimony ores was realized by wavelength dispersive X-ray fluorescence spectrometry. The corrosion problems of Pt-Au alloy crucibles by antimony sulfide ore containing high content of sulfur was solved by pre-oxidizing the sample with LiNO₃ at low-temperature. The calibration curve which could satisfy the quantitative determination requirements of each component was established with eight antimony certified reference materials (CRMs) and calibration samples synthesized with CRMs. Besides, theoretical α coefficient method was adopted to correct matrix effect. After precision test, the relative standard deviation (RSD, n=12) of the determination of the components in antimony ore samples was between 0.1%-9.7%. The accuracy of CRMs and synthesized samples was validated, and the analytical results were consistent with the certified value or reference value.