熔融制样—X射线荧光光谱法测定碳酸盐岩石中主次量元素及烧失量

碳酸盐岩石的主要成分为碳酸钙、碳酸镁,采用熔融制样—X射线荧光光谱法对其主次量元素进行测定时,最难解决的是烧失量大导致测定结果偏低问题。如果以灼烧后的试样制备试料片,灼烧后的试料极易吸收空气中的水分和二氧化碳,同样会使测定结果偏低,且检测流程繁琐。该文采用试样经烘干后直接熔融制样,采用基本参数法NBSGSC得到理论Alphas系数,结合烧失量(LOI)计算理论的元素间校正因子,基于浓度的乘法模式对标准曲线进行校正,消除了烧失量对各组分测定的影响;各组分标准曲线的相关系数0.998 0~0.999 9;测定结果的相对标准偏差RSD(n=11)为0.28%~5.01%;通过仪器设定,自动计算出试样的烧失量,无需再通过化学法进行测定。该检测方法可实现一次熔样,完成10种元素及烧失量同时测定,且分析结果精密度好、准确度高、方法快速简便、大大降低了分析成本,适用于碳酸盐岩石的批量检测。

Determination of primary and secondary elements in carbonate rocks by fusion sample preparation-XRF and the loss on ignition

Carbonate rocks mainly consist of CaCO3 and MgCO3 . When fusion sample preparation-XRF deter-mines main and secondary elements,it is difficult to deal with large loss on ignition that results in lower determination value. If prepared by ignited samples,the specimen is likely to absorb H2 O and CO2 in the air,which will also result in lower determination value besides being a lengthy detection flowsheet. The paper immediately prepared the sample by fusing after the sample was dried,employed NBSGSC to obtain Alphas coefficient,calculated correction factors between elements based on LOI,corrected standard curves based on multiplication patterns of concentration,and finally eradi-cated the influence of LOI on the determination of each element; the correlation coefficient of the standard curve of each composition was 0. 998 0-0. 999 9;the RSD(n=11) of the determination result was 0. 28 % -5. 01 %;LOI was automatically calculated by instrument settings,saving the process of chemical determination. The detection me-thod can complete 10 element LOI determination at the same time in one fusion. And the analysis results are precise and accurate. The method is fast and simple,greatly reduces analysis cost and is applicable to batch tests of carbonate rocks.