粉末压片-X射线荧光光谱法测定铋矿石中铋及主量组分

利用X射线荧光光谱仪(XRF)结合粉末压片法来测定铋矿石中铋及主量组分。通过向样品中加入稀释剂硼酸来减小基体效应,并加入氧化镧来保持样品总质量吸收系数稳定。实验选取0.5g样品、0.5g氧化镧和2.5g硼酸混合均匀作为待测样品。为了解决铋矿石标准样品缺乏的问题,将钨铋矿石成分分析标准物质GBW07284与水系沉积物成分分析标准物质GBW07317以不同质量比例(1∶1,1∶2,1∶3,1∶5)混合配制成铋元素含量具有一定梯度的校准样品。样品的混合均匀性实验表明各元素测定结果的相对标准偏差(RSD,n=12)在0.26%~4.0%之间。方法中各元素的检出限为0.004%~0.95%。通过对GBW07241的验证,测定值均在误差范围内,各组分测定结果的相对标准偏差(RSD,n=11)在4%以下。通过对多个样品的分析比对,实验方法的分析结果与常规化学测定值基本一致,符合地质样品分析规范要求。

Determination of bismuth and major components in bismuth ore by X-ray fluorescence spectrometry with pressed powder pellet

The contents of bismuth and major components in bismuth ore by X-ray fluorescence spectrometry (XRF) with pressed powder pellet sample preparation. The matrix effect was reduced by adding boric acid as diluting agent into sample. Meanwhile, the lanthanum oxide was added to stabilize the total mass absorption coefficient of sample. 0.5g of sample, 0.5g of lanthanum oxide and 2.5g of boric acid were uniformly mixed for measurement. In order to solve the problem of lack in standard sample, the certified reference materials of tungsten-bismuth ore (GBW07284) and stream sediment (GBW07317) were mixed at different ratios (1∶1, 1∶2, 1∶3 and 1∶5) to prepare calibration sample with certain content gradient of bismuth. The mixing uniformity experiment of sample showed that the relative standard deviations (RSD, n=12) values of elements were between 0.26% and 4.0%. The detection limits of elements in method were 0.004%-0.95%. The proposed method was applied to the analysis of certified reference material (GBW07241), and the measured values were within the range of error. RSDs (n=11) of measurement results were below 4%. The analysis and comparison of multiple samples indicated that measured values by proposed method were consistent with those obtained by the conventional chemical method. The proposed method could meet the requirements of analysis criteria of geological samples.