熔融制样-X射线荧光光谱法测定锰铁、硅锰合金中锰硅磷

熔融制样-X射线荧光光谱法(XRF)测定合金样品,需重点解决样品前处理中合金样品侵蚀铂-黄金坩埚的难题。实验以无水四硼酸锂为熔剂,过氧化钡、碳酸锂为氧化剂,建立了熔融制样-X射线荧光光谱法测定锰铁、硅锰合金中锰、硅、磷含量的方法。实验方法采用低温预氧化熔融制样技术,解决了锰铁、硅锰合金对铂-黄金坩埚腐蚀的难题;应用碳烧失基和消去项消除了锰铁、硅锰合金中烧失/烧增量对检测结果的影响。试验进一步探讨了稀释比、氧化剂加入量、熔融温度、熔融时间等条件对锰铁、硅锰合金中锰、硅、磷含量的影响,得出最佳试验条件:稀释比(m_{无水四硼酸锂}∶m_试样)为7∶0.25;氧化剂量分别为过氧化钡 0.5000g、碳酸锂0.5000g;熔融温度为1100℃;静置熔融时间为150s。锰、硅、磷的方法检出限分别为10、25、18μg/g。在最佳实验条件下分别对锰铁(GSB03-1687-2004)、硅锰合金(GSB03-1316-2000)国家标准样品进行精密度考察,锰测定结果的相对标准偏差(RSD)分别为0.088%和0.053%(锰),0.35%和1.1%(硅),2.9%和1.2%(磷)。对于锰铁、硅锰合金实际样品,实验方法与国标方法的测定结果一致性较好,能满足常规分析要求。

Determination of manganese,silicon, phosphorus in ferromanganeseand silicomanganese alloy by X-ray fluorescence spectrometrywith fusion sample preparation

During the determination of alloy samples by X-ray fluorescence spectrometry (XRF) with fusion sample preparation, the problem of platinum-gold crucible corrosion in alloy sample pretreatment should be emphatically solved. Anhydrous lithium tetraborate was selected as flux and barium dioxide-lithium carbonate was used as oxidizer. A determination method of manganese, silicon and phosphorus in ferromanganese and silicomanganese alloy by XRF with fusion sample preparation was established. The fusion sample preparation technique with low temperature preoxidation was adopted to solve the problem of platinum-gold crucible corrosion by ferromanganese and silicomanganese alloy. The influence of ignition loss or ignition increase of ferromanganese and silicomanganese alloy on determination results was eliminated with carbon ignition loss base and elimination term. The effect of experimental conditions (such as dilution ratio, addition amount of oxidizer, fusion temperature and fusion time) on determination of manganese, silicon and phosphorus in ferromanganese and silicomanganese alloy was further discussed. The following optimum conditions were obtained: the dilution ratio (m_{Anhydrous lithium tetraborate}∶m_Sample) was 7∶0.25; 0.5000g of barium dioxide and 0.5000g of lithium carbonate were used as oxidizer; the fusion temperature was 1100℃; the static fusion time was 150s. The detection limit of manganese, silicon and phosphorus in method was 10μg/g, 25g/g and 18μg/g, respectively. The precision tests were conducted with national certified reference materials of ferromanganese (GSB03-1687-2004) and silicomanganese alloy (GSB03-1316-2000) under the optimal experimental conditions. The relative standard deviations (RSD) of determination results were 0.088% and 0.053% (Mn), 0.35% and 1.1% (Si), and 2.9% and 1.2% (P), respectively. The actual samples of ferromanganese and silicomanganese alloy were determined according to the experimental method, and the results were consistent with those obtained by the national standard method. The proposed method could meet the requirements of routine analysis.