微波消解-火焰原子吸收光谱法测定铜精矿中银

以王水为消解体系,采用3步程序升温微波消解法处理样品,选择8%(体积分数)王水为测定介质,实现了火焰原子吸收光谱法(FAAS)对铜精矿样品中1.6~600.0g/t银的测定。干扰试验表明,样品中的铜和铁对银测定的干扰可忽略。在选定的实验条件下,以银质量浓度为横坐标,测得的吸光度为纵坐标绘制校准曲线,其线性相关系数为0.9998。方法检出限为1.6g/t。采用实验方法对3个铜精矿标准物质分别测定11次,测定值与认定值一致,相对标准偏差(RSD)为0.23%~0.66%。选取5组不同银含量的铜精矿样品,按照实验方法测定,并根据测得银含量的不同范围,分别与国标方法GB/T 3884.2—2012中的酸溶-FAAS和火试金-滴定法测得结果进行对比,结果表明,二者基本吻合。

Determination of silver in copper concentrate by microwave digestion-flame atomic absorption spectrometry

The sample was treated by microwave digestion with three-step temperature program using aqua regia as the digestion system. With 8% (volume) aqua regia was selected as determination medium, the determination of silver within range of 1.6-600.0g/t in copper concentrate samples was realized by flame atomic absorption spectrometry (FAAS). The interference tests indicated that the interference of copper and iron in sample with the determination of silver could be ignored. Under the selected experimental conditions, the calibration curve was prepared with the mass concentration of silver as x-axis and the measured absorbance as y-axis. The linear correlation coefficient was 0.9998. The detection limit of method was 1.6g/t. Three certified reference materials of copper concentrate were determined according to the proposed method for 11 times, respectively. The results were consistent with the certified values, and the relative standard deviations (RSD, n=11) were between 0.23% and 0.66%. Five groups of copper concentrate samples with different silver contents were selected and determined according to the proposed method. Based on the range of silver content, the determination results were compared with acid dissolution-FAAS and fire assaying-titration method in national standard GB/T 3884.2-2012, respectively. It was indicated that the determination results were basically consistent.