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    熔融制样-X射线荧光光谱法测定工业硅中总硅、二氧化硅和其他杂质组分

    XRFS Determination of Total Silicon, Silicon Dioxide and Others Impurity Elements in Industry Silicon with Sample Preparation by Fusion

    • 摘要: 将四硼酸锂内衬坩埚熔融制样方法应用于X射线荧光光谱法测定工业硅中总硅、二氧化硅和其他杂质组分(铝、铁、钙、镁、钛)。在熔融制样前,样品(1.000 0 g)经直接灼烧(700~750℃)计算灼减量并除去样品中碳。称取上述灼烧后的样品0.200 0 g,与碳酸锂1.700 g和600 g·L-1硝酸铵溶液0.1~0.3 mL混匀后移入四硼酸锂内衬坩埚中,于710~720℃预氧化10~12 min。将此经预氧化的混合物及其内衬坩埚一起转移至预置有3.000 g硼酸的铂金坩埚中,加入400 g·L-1溴化铵溶液0.1~0.4 mL,于熔样机中静置熔融8 min,摇动熔融12 min,冷却,脱模后即得样品的玻璃片。选取测定元素的氧化物,按0.200 0 g称样量模拟制备了5个校准样片,各组分的质量分数在一定范围内与其对应的X射线荧光强度呈线性关系,提出了样品中二氧化硅含量的计算公式。方法用于5个工业硅样品的分析,测定结果与湿法分析测定值相符。

       

      Abstract: The method of sample preparation by fusion in a Li2B4O7-lined crucible was applied to the XRFS analysis of industrial silicon for determination of total silicon, silicon dioxide and others impurity elements (Al, Fe, Ca, Mg and Ti). Before the fusion procedure, the sample (1.000 0 g) should be ignited directly at 700℃ to 750℃ to give the value of ignition loss and to expell carbon in the sample. 0.200 0 g of the ignited sample was mixed thoroughly with 1.700 g of Li2CO3 and 0.1-0.3 mL of 600 g·L-1 NH4NO3 solution, and the mixture was transferred into the Li2B4O7-lined crucible and preoxidized for 10 to 12 min at 710℃ to 720℃. The preoxidized mixture together with the lined crucible was then transferred into a Pt-Au crucible in which 3.000 g of boric acid had been added preliminarily, and 0.1-0.4 mL of 400 g·L-1 NH4Br solution was added and the fusion procedure was carried out in a sample fusion apparatus, for 8 min under stationary mode and followed for 12 min under shaking mode. After cooling, a glassy slice of the melt of the sample was demoulded from the crucible. Five melts of calibration samples (equivalent to 0.200 0 g of each sample) were prepared by mixing oxides of determined elements, and treated in the same way as the fusion of sample. Linear relationships between values of XRF intensity and mass fraction of each components were kept in definite ranges. A formula for calculation of SiO2 in the sample was proposed. The proposed method was applied to analyze 5 samples of industrial silicon, giving results in consistency with the values given by wet analysis.

       

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