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    氧化钙固硫-催化裂解-金汞齐富集-冷原子吸收光谱法测定混合铅锌精矿中汞的含量

    Determination of Mercury in Mixed Lead-Zinc Concentrates by Calcium Oxide Sulfur Fixation-Catalytic Pyrolysis-Gold Amalgamation Enrichment-Cold Vapor Atomic Absorption Spectrometry

    • 摘要: 样品经研磨、干燥、冷却后,分取0.1000 g平铺于样品舟中,加入约0.05 g氧化钙,混匀,再在混合物表面覆盖约0.05 g氧化钙,在热解温度800 ℃、热解时间180 s、检测波长253.7 nm 的条件下采用冷原子吸收光谱法测定。结果显示:汞的质量分别在1~20 ng和20~1 000 ng内和对应的吸光度呈非线性二次函数关系,检出限为0.63 ng。方法用于8个不同物相组成的不同含硫量的混合铅锌精矿样品的分析,汞测定值的相对标准偏差(n=11)均小于5.0%,回收率为96.4%~107%,测定值与标准方法YS/T 461.6—2013的基本一致,12家实验室的11次平行测试所得的方法重现性限(r)为r=0.057 5X+0.009,再现性限(R)为R=0.082 1X+0.036(X为样品中汞的实测质量分数)。

       

      Abstract: After grinding, drying, and cooling, 0.100 0 g of the sample was taken, evenly spread on a sample boat, and mixed with approximately 0.05 g of calcium oxide. Then, the mixture was covered with another approximately 0.05 g of calcium oxide. The determination was conducted by cold vapor atomic absorption spectrometry at 800 ℃ for 180 s, with a detection wavelength of 253.7 nm. It was shown that the mercury masses exhibited nonlinear quadratic relationships with the corresponding absorbances in the ranges of 1–20 ng and 20–1 000 ng, respectively, and the detection limit was 0.63 ng. The proposed method was applied to the analysis of 8 mixed lead-zinc concentrate samples with different sulfur contents and varying phase compositions. RSDs (n=11) of the mercury determined values were all less than 5.0%, with recoveries ranging from 96.4% to 107%. The determined values were consistent with those obtained by the standard method YS/T 461.6—2013. The reproducibility limit (r) derived from 11 parallel tests conducted by 12 laboratories was r=0.057 5X+0.009, and the reproducibility limit (R) was R=0.082 1X+0.036 (where X was the determined mass fraction of mercury in the sample).

       

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