火焰原子吸收光谱法测定铜精矿中钾和钠

铜精矿中钾和钠杂质含量对铜冶炼工艺有重要影响。采用盐酸-硝酸-氢氟酸-高氯酸分解试样,在5%盐酸介质中,采用空气-乙炔火焰,分别以K 766.5 nm、Na 589.0 nm作为测定波长,建立了火焰原子吸收光谱法(FAAS)测定铜精矿中钾和钠的方法。在优化的实验条件下。钾和钠的质量浓度均在1.00～5.00 μg/mL范围内与其对应的吸光度呈良好的线性关系,相关系数分别为0.999 8和0.999 9。钾和钠的方法检出限分别为0.086 ng/mL和0.056 μg/mL,定量限分别为0.287 ng/mL和0.187 ng/mL。干扰试验表明,样品中共存元素不干扰钾和钠的测定。采用实验方法对3个铜精矿成分分析标准物质分别测定11次,测定值与标准值的相对误差为-7.69%~5.40%,相对标准偏差(RSD,n=11)为0.44%~3.7%。将实验方法应用于铜精矿样品中钾和钠,测定结果的相对标准偏差(n=11)为0.55%～2.4%,加标回收率为96%～105%。

Determination of potassium and sodium in copper concentrate by flame atomic absorption spectrometry

The impurity contents of potassium and sodium in copper concentrate had an important influence on the copper smelting process. The sample was decomposed with hydrochloric acid-nitric acid-hydrofluoric acid-perchloric acid. The determination method of potassium and sodium in copper concentrate by flame atomic absorption spectrometry (FAAS) was established with air-acetylene flame. The determination medium was 5% hydrochloric acid. The determination wavelengths were 766.5 nm and 589.0 nm respectively for potassium and sodium. Under the selected experimental conditions, the mass concentration of potassium and sodium in range of 1.00-5.00 μg/L showed good linear relationship with the corresponding absorbance. The correlation coefficient was 0.999 8 and 0.999 9, respectively. The limit of detection of this method for potassium and sodium was 0.086 ng/mL and 0.056 μg/mL, respectively. The limit of quantification was 0.287 ng/mL and 0.187 ng/mL, respectively. The interference tests showed that the coexisting elements in sample had no interference with the determination of potassium and sodium. Three certified reference materials of copper concentrate for composition analysis were determined for 11 times according to the experimental method. The relative errors between the results and certified values were -7.69%-5.40%, and the relative standard deviations (RSDs, n=11) were 0.44%-3.7%. The proposed method was applied for the determination of potassium and sodium in copper concentrate sample. The RSDs (n=11) of determination results were 0.55%-2.4%, and the recoveries were 96%-105%.