熔融制样-X射线荧光光谱法测定铬铁中铬硅磷钛

采用传统湿法测定铬铁中主次元素含量时操作繁琐、不易掌握;熔融制样-X射线荧光光谱法测定高碳铬铁中铬、硅和磷的含量已有应用。为拓宽X射线荧光光谱(XRF)检测铬铁的应用,采用四硼酸锂熔剂挂壁打底保护铂合金坩埚,以四硼酸锂和碳酸锂做熔剂,用过氧化钡和硝酸钠做氧化剂对样品进行处理,实现了X射线荧光光谱对铬铁中铬、硅、磷、钛的测定。先在高频熔融炉中对样品进行预氧化,经过预氧化处理将样品中的单质元素转化成氧化物,避免高温状态下单质元素与铂形成低温共熔体而腐蚀损坏铂金坩埚,解决了熔融法处理铬铁试样时容易腐蚀坩埚的难点。在最佳实验条件下,采用高碳、中碳、低碳铬铁标准样品和用高纯铁粉和铬铁标样配制的合成标样建立相关校准曲线,铬、硅、磷和钛校准曲线的相关系数均大于0.993。对高碳铬铁标准样品进行精密度考察,4种元素测定结果的相对标准偏差(RSD,n=11)在0.068%～3.9%范围内。对铬铁标准样品进行分析,测定值与认定值相吻合。采用实验方法对铬铁样品中各元素进行测定,所得结果和湿法测得值一致性较好。

Determination of chromium,silicon, phosphorus and titanium in ferrochromium by X-ray fluorescence spectrometry with fusion sample preparation

During the determination of major and minor elements in ferrochromium by conventional wet method, the operation was complicated and difficult to master. X-ray fluorescence spectrometry (XRF) coupled with fusion sample preparation had been applied to the determination of chromium, silicon and phosphorus in high-carbon ferrochromium. In order to broaden the application of XRF in detection of ferrochromium samples, the lithium tetraborate flux was hanged on the wall for protection of platinum alloy crucible. Consequently, the determination of chromium, silicon, phosphorus and titanium in ferrochromium was realized by XRF with lithium tetraborate and lithium carbonate as flux and barium peroxide and sodium nitrate as oxidizer. The sample was pre-oxidized in high frequency fusion machine. The elementary elements in sample were converted into oxides to avoid the corrosion of platinum alloy crucible due to the formation of low-temperature eutectic formed by elementary elements and platinum at high temperatures. The corrosion problem of crucible during the treatment of ferrochromium samples by fusion method was solved. Under the optimal experimental conditions, the related calibration curves were established with certified reference materials of high-carbon, medium-carbon and low-carbon ferrochromium and the synthetic reference materials prepared by high-purity iron powder and ferrochromium certified reference materials. The correlation coefficients of calibration curves for chromium, silicon, phosphorus and titanium were all higher than 0.993. The precision test was conducted with high-carbon ferrochromium certified reference materials. The relative standard deviations(RSD, n=11) of determination results for four elements were between 0.068% and 3.9%. The ferrochromium certified reference materials was analyzed and the results were consistent with the certified values. The experimental method was applied to the determination of elements in ferrochromium samples, and the results were consistent with those obtained by wet method.