熔融制样-X射线荧光光谱法测定生铁中硅锰磷

实验以四硼酸锂挂壁形成熔剂坩埚来确保铂-金坩埚在氧化熔融过程中不被试样腐蚀,以硝酸(1+1)氧化溶解生铁样品,低温蒸发剩余液体,再加入碳酸锂熔融制备玻璃片,建立了X射线荧光光谱法(XRF)测定生铁中硅、锰、磷含量的方法。实验表明,四硼酸锂、碳酸锂和样品的质量比为30:5:1,加入3~5mL 300g/L的碘化铵溶液作脱模剂,在1050℃熔融20min制得的玻璃片强度高、质地均匀、检测面光洁。使用生铁、锰矿石、铁矿石标准物质建立硅、锰、磷校准曲线,校准曲线线性相关系数和回归精度均较好。硅、锰、磷的检出限在1.32~5.60μg/g之间。对同一生铁样品进行精密度考察,各元素测定结果的相对标准偏差(RSD,n=12)介于0.83%~1.8%之间;正确度结果表明,生铁标准样品的测定结果与认定值的误差在国标允许范围内。

Determination of silicon,manganese and phosphorus in pig iron by X-ray fluorescence spectrometry with fusion sample preparation

The flux crucible was formed using lithium tetraborate on wall to prevent platinum-gold crucible from corrosion by sample in oxidation fusion process. The pig iron sample was oxidized and dissolved by nitric acid (1+1). The residual liquid was evaporated at low temperature. Then lithium carbonate was added to prepare glass bead by fusion. The determination method of silicon, manganese and phosphorus in pig iron by X-ray fluorescence spectrometry (XRF) was established. The experiments showed that the prepared glass bead was tough, uniform and smooth under the following conditions: the mass ratio of lithium tetraborate, lithium carbonate and sample was 30:5:1; 3-5mL of 300g/L ammonium iodide solution was used as release reagent; the mixture was fused at 1050℃ for 20min. The calibration curves of silicon, manganese and phosphorus were established with certified reference materials of pig iron, manganese ore and iron ore. The linear correlation coefficient and regression accuracy of calibration curves were good. The limits of detection for silicon, manganese and phosphorus were between 1.32μg/g and 5.60μg/g. The precision test was investigated using one pig iron sample. The relative standard deviations (RSD, n=12) of determination results of elements were between 0.83% and 1.8%. The accuracy test results showed that the error between the determination values and certified values of certified reference material of pig iron was within the allowable range specified in national standard method.