火焰原子吸收光谱法测定冰铜中钴

在体积分数为5%的盐酸介质中,使用空气-乙炔火焰,以240.7nm为测定波长,建立了火焰原子吸收光谱法(FAAS)测定冰铜中钴的方法。溶样试验表明,采用 20mL王水、1mL氢氟酸和2mL高氯酸溶样后加入10mL盐酸(1+1)溶解盐类,大多数情况下可将试样溶解完全;如果试样溶解不完全,需要补加5mL硝酸,继续加热至棕红色烟雾消失,再加入2mL高氯酸加热至白烟冒尽可将试样溶解完全。在选定的仪器条件下,钴的质量浓度与吸光度呈良好的线性关系,相关系数为0.9992,方法检出限为0.0075μg/mL。干扰试验表明,试样中的共存元素不干扰钴的测定。将实验方法应用于4个冰铜样品中钴的测定,对测定结果进行格拉布斯(Grubbs)检验,结果表明11次平行测定的结果无异常值,相对标准偏差(RSD,n=11)在1.7%~8.5%之间。采用实验方法对2个不同钴含量阶梯的冰铜试样进行测定,测得结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,加标回收率在90%~105%之间。分别在6家实验室采用实验方法进行冰铜试样的测定,方法的重复性限为r=0.0006+0.0429m;再现性限为R=0.0046+0.0647m。

Determination of cobalt in copper matte by flame atomic absorption spectrometry

The determination method of cobalt in copper matte by flame atomic absorption spectrometry (FAAS) was established in 5% (volume fraction) hydrochloric acid medium using air-acetylene flame. The determination wavelength was 240.7nm. The sample dissolution experiments indicated that the sample could be completely dissolved in most cases under the following conditions: the sample was dissolved in 20mL of aqua regia, 1mL of hydrofluoric acid and 2mL of perchloric acid; then 10mL of hydrochloric acid (1+1) was added to dissolve the salts. If the dissolution of sample was not complete, 5mL of nitric acid should be added. The solution was further heated until the brown red fume disappeared. Then 2mL of perchloric acid was added until white fume appeared. The sample could be completely dissolved. Under the selected instrumental conditions, the mass concentration of cobalt showed good linear relationship with the absorbance. The correlation coefficient was 0.9992, and the detection limit was 0.0075μg/mL. The interference tests showed that the coexisting elements in sample had no interference with the determination of cobalt. The experimental method was applied for the determination of cobalt in four copper matte samples. The Grubbs test of determination results was conducted. The results showed that there was no abnormal value in parallel determination (n=11). The relative standard deviations (RSD, n=11) were between 1.7% and 8.5%. Two copper matte samples with different cobalt content gradients were determined according to the experimental method, and the found results were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES). The recoveries were between 90% and 105%. The determination of copper matte sample was conducted in six laboratories according to the experimental method. The repeatability limit of method was r=0.0006+0.0429m, and the reproducibility limit was R=0.0046+0.0647m.