X射线荧光光谱法测定萤石中氟化钙、二氧化硅、氧化铝、全铁的含量

XRFS Determination of CaF_2,SiO_2,Al_2O_3 and Total Iron in Fluorspar

应用X射线荧光光谱法(XRFS)测定了萤石中氟化钙、二氧化硅、氧化铝和全铁的含量。采用熔融法制备样块,称取粒径小于0.125mm的试样1.000g于铂坩埚中与硝酸钾0.2g、碳酸锂1.0g及无水四硼酸锂5.0g混合均匀,加入150g.L-1溴化锂溶液3滴,于1 050℃熔融20min,所得熔块用XRFS对上述4种组分进行测定。对含有还原性物质的试样采用先在铂坩埚中加入无水四硼酸锂熔融,使熔剂均匀粘涂于坩埚内壁的下部和底部,冷却后再用硝酸钾及碳酸锂按程序在低温预氧化后升至高温对样品进行熔融,所得熔块用于XRFS分析,用标准样品按试验方法制备工作曲线。应用此法分析了4个萤石样品,上述组分的测定值与化学法的测定值相符。

Contents of CaF2, SiO2, Al2O3 and total iron （TFe） in fluorspar were determined by XRFS. Cube samples for XRFS determinations were prepared by fusion. 1. 000 g （size ca. 0. 125 mm） of the sample was mixed thoroughly with KNO3 （0. 2 g）, Li2CO3 （1.0 g） and Li2B4O7 （5.0 g） in a Pt crucible, and after addition of 3 drops of 150 g · L^-1 LiBr solution, the mixture was fused at 1 050 ℃ for 20min. The melt after cooling to room temperature was used for determination of the 4 components by XRFS. For samples containing reductive substances, the fusion process should be modified. Li2NO7 should be added to the Pt crucible to have the melt coated on the inner wall of the crucible at lower, and botton parts. After cooling, KNOa and Li2 CO3 were added to the crucible, after pre-oxidation at programmed low temperatures, fusion of the sample was performed as above. The melt was used for determination of the 4 components. Working curves were prepared by using standard samples. Four fluorspar samples were analyzed by the proposed method, giving results in consistency with the results found by chemical methods.