封闭酸溶—泡塑富集火焰原子吸收光谱法测定矿石中金

    Determination of Gold in Ore Samples by Flame Atomic Absorption Spectrometry of Sealed Dissolution after Adsorption using Polyurethane Foam

    • 摘要: 这是一篇矿物分析领域的论文。试样焙烧后采用50%王水水浴封闭溶样,用0.25 g泡塑振荡富集样品中的金,泡塑用水冲洗去除矿渣和酸后,采用1%硫脲对金进行热解脱,建立了封闭酸溶—泡塑富集火焰原子吸收光谱法测定矿石中金的方法。实验讨论了部分含金矿石样品的焙烧处理方法;考查了封闭溶样时间、泡塑前处理方法、富集温度、测定液温度等影响因素,结果表明:封闭酸溶时间为2 h,可满足常见含金矿石样品中金的分解,泡塑经5%HCl处理后,在室温下对金的富集回收率达到了95%以上,测定过程中应确保测定液温度、标准溶液温度与室温相一致。金标准溶液按照实验方法进行富集与解脱处理制备而成。在选定的实验条件下,方法检出限为0.13 μg/g,定量限为0.43 μg/g,测定上限为80 μg/g。方法加标回收率为98.7%~101%,精密度(RSD,n=5)为1.10%~2.07%。应用本方法对含金矿石标准物质及标准参考样品中的金进行测定,测定值与认定值基本一致。

       

      Abstract: This is an essay in the field of mineral analysis. After the samples were roasted and digested in 50% aqua regia by sealed dissolution,the gold in ore samples were adsorbed by 0.25g polyurethane foam during the oscillating, the polyurethane foam was washed to removing the slurry and acid, and gold was eluted out from polyurethane foam with 1% thiourea. Thus, a determination method of gold in ore samples by flame atomic absorption spectrometry of sealed dissolution after adsorption with polyurethane foam was established.The roasting method of some special gold ore samples was discussed.The conditions of sealed dissolution time, foam pretreatment, adsorption temperature and solution temperature were optimized, the results showed that when the sealed dissolution for 2 h, the gold was completely decomposed. After the polyurethane foam was treated with 5%HCl, the adsorption recoveries of gold could reach 95% at room temperature, the temperature of solution and standard solution shall be consistent with room temperature during determination. The calibration curve was prepared by foam adsorption and desorption process. Under the selected experimental conditions, the limit of detection was 0.13 μg/g, the limit of quantification was 0.43 μg/g, and the upper limit of determination was 80 μg/g. The standard recoveries were between 98.7% and 101%, the relative standard deviations(RSD, n=5) were between 1.10% and 2.07%. Verified by the determination of gold ore certified reference materials, the results were basically consistent with the certified value.

       

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