铜尾矿在微波消解仪中经盐酸-硝酸(3+1)溶液和过氧化氢消解。从所得消解液中分取部分试液,加入1-(2-吡啶偶氮)-2-萘酚(PAN)溶液、Triton X-100溶液、pH 6.0的氢氧化钠-磷酸二氢钾缓冲溶液及饱和氯化钠溶液,加水定容至15 mL,于70 ℃加热30 min,使铜(Ⅱ)与PAN络合并溶入Triton X-100相中,实现铜(Ⅱ)的浊点萃取分离。弃去水相,于Triton X-100相中,加入水及3滴盐酸,用石墨炉原子吸收光谱法测定其中的铜量。铜的质量浓度在0.5~20 μg·L-1范围内与吸光度呈线性关系,检出限(3σ)为0.36 μg·L-1。应用本方法分析了铜尾矿样品,并用标准加入法做回收试验,测得回收率在101%~105%之间,测定值的相对标准偏差(n=6)在3.0%~3.8%之间。

Sample of copper tailings was digested with a mixture of HCl-HNO3 (3+1) and H2O2 in a microwave digestor. An aliquot was taken from the solution obtained and 1-(2-pyridineazo)-2-naphthol (PAN), Triton X-100, NaOH-KH2PO4 buffer solution of pH 3.0 as well as NaCl saturated solution were added. After diluting to 15 mL with water, the solution was heated at 70 ℃ for 30 min, to have the Cu2+ separated in form of its complex with PAN by the cloud point extraction. After discarding the water phase, the Triton X-100 phase was taken up with water and 3 drops of HCl. The content of copper in this solution was determined by GF-AAS. Linear relationship between values of absorbance and mass concentration of Cu2+ was kept in the range of 0.5-20 μg·L-1, with detection limit (3σ) of 0.36 μg·L-1. The proposed method was applied to the analysis of a sample of copper tailings, and recovery was tested by standard addition method giving values of recovery and RSD′s (n=6) in the ranges of 101%-105% and 3.0%-3.8% respectively.