熔融制样-能量色散X射线荧光光谱法测定铝镁尖晶石中氧化铝、氧化镁和氧化硅

Determination of aluminum oxide,magnesium oxide and silicon oxide in alumina-magnesia spinel by energy dispersive X-ray fluorescence spectrometry with fusion sample preparation

标准中针对铝镁尖晶石的分析多采用湿法或者波长色散X射线荧光光谱法。随着能量色散X射线荧光光谱仪的迅速发展,其在多个行业的元素分析中得到了广泛应用。实验通过熔融制样,利用能量色散X射线荧光光谱仪建立了铝镁尖晶石中Al_2O_3、MgO和SiO_2的测定方法。由于铝镁尖晶石无现成标准样品,实验选用合适的特优矾土、高纯镁砂等标准样品;同时,根据其生产工艺将特优矾土标准样品和高纯镁砂标准样品,以及氧化铝基准物质和高纯镁砂标准样品合成系列校准样品。固定称样量为0.500 0g,样品与无水四硼酸锂(Li_2B_4O_7)熔剂的稀释比为1∶16,以4滴0.5g/mL NH_4Br溶液为脱模剂在1 150℃下进行熔样的效果较好。以标准样品和校准样品绘制校准曲线,Al_2O_3、MgO、SiO_2校准曲线的均方根(RMS)分别为0.916、0.888和0.029。对镁铝砖标准样品进行精密度考察,Al_2O_3、MgO和SiO_2的相对标准偏差(RSD,n=5)分别为1.4%、0.42%和3.1%;对铝镁砖标准样品和铝镁耐火物标准样品以及铝镁尖晶石试样进行分析,Al_2O_3、MgO、SiO_2的分析结果与认定值或湿法测定值基本一致,满足生产检验要求。

The analysis of alumina-magnesia spinel in standards mainly adopted wet method or wavelength dispersion X-ray fluorescence spectrometry.With the rapid development of energy dispersive X-ray fluorescence spectrometer(EDXRF),it has been widely used for the elemental analysis in many industries.A determination method of Al2O3,MgO and SiO2 in alumina-magnesia spinel by EDXRF with fusion sample preparation was established.Since there were no ready-made certified reference materials(CRMs)of alumina-magnesia spinel,proper CRMs such as special bauxite and high-purity magnesia were selected in experiments.Meanwhile,a series of calibration samples were synthesized with special bauxite CRM and high-purity magnesia CRM,as well as aluminum oxide primary standard and high purity magnesia CRM according to the production process of alumina-magnesia spinel.When the sample mass as was fixed at0.500 0 g,the dilution ratio of sample to anhydrous lithium tetraborate(Li2B4O7)flux was 1∶16,and four drops of 0.5 g/mL NH4Br solution was used as the releasing reagent,the melting effect of sample was good at 1 150℃.The calibration curves were prepared with the selected CRMs and calibration sample.The root-mean-square(RMS)of calibration curves for Al2O3,MgO and SiO2 were 0.916,0.888 and 0.029,respectively.The precision test was conducted with the CRMs of magnesia-alumina brick.The relative standard deviation(RSD,n=5)of determination results for Al2O3,MgO and SiO2 were 1.4%,0.42%and 3.1%,respectively.The CRMs of magnesia-alumina brick and alumina-magnesia refractory as well as alumina-magnesia spinel actual sample were analyzed according to the experimental method.The results of Al2O3,MgO and SiO2 were basically consistent with the certified values or those obtained by the wet method.The proposed method could meet the requirements of production inspection.