火焰原子吸收光谱法测定红土镍矿中的铅

样品用盐酸-硝酸溶解,氢氟酸挥发硅,高氯酸冒烟除去氢氟酸,然后以稀硝酸溶解可溶性盐类,火焰原子吸收光谱法测定红土镍矿中铅的含量。考察了不同的酸对样品的溶解效果,对介质酸度和共存元素干扰情况进行了实验。结果表明:盐酸-硝酸-氢氟酸-高氯酸可以将样品消解完全;5%以内的硝酸不影响铅的测定;100 mL体积内,100 mg铁、6 mg镍、1 mg铜、5 mg钙、2 mg锰、1 mg铬、1 mg钴、1 mg锌等共存元素对0.1 mg铅的测定不产生干扰。在选定的仪器工作参数下,Pb的检出限为0.044μg/mL,加标回收率为97%～106%,测定值与电感耦合等离子体发射光谱法结果一致。方法重复性好、准确度高,可满足准确测定红土镍矿中铅含量的分析要求。

Determination of Lead in Laterice Nickel Ore by Flame Atomic Absorption Spectrometry

Laterice nickel ore was digested with mixed acids of HCl and HNO3 mixed acids.HF was used to remove silicon,and residual HF was volatilized by using HClO4.Lead content in the HNO3 solution was determined by Flame Atomic Absorption Spectrometry.The different acid digestion systems and interferences of coexistent elements are presented in this paper.The results showed that the samples were completely dissolved by HCl-HNO3-HF-HClO4 mixed acids.The Pb level content was not influenced by HNO3 when its acidity was below 5%(V/V).The coexistent elements of Fe(1000 μg/mL),Ni(60 μg/mL),Cu(10 μg/mL),Ca(50 μg/mL),Mn(20 μg/mL),Cr(10 μg/mL),Co(10 μg/mL) and Zn(10 μg/mL) did not interfere with the Pb result(1 μg/mL).The detection limit was 0.044 μg/mL at selected working conditions.The accuracy of the Pb content was verified by adding a standard solution to the laterice nickel ore.The recoveries ranged from 97% to 106%,and the results of this method were in agreement with inductively coupled plasma atomic emission spectrometry.The proposed method is a useful technique with good repeatability and accuracy.