火焰原子吸收光谱法测定红土镍矿中铜、锌、铬含量

红土镍矿样品用盐酸、硝酸分解,残渣用焦硫酸钾熔融,在稀盐酸介质中,采用氘灯扣除背景,分别用原子吸收光谱仪于波长324.8,213.9,357.9 nm处,使用空气–乙炔火焰,测量铜、锌、铬的含量。在最佳实验条件下,铜、锌、铬的质量浓度分别在0.50～2.50,0.30～1.50,0.50～4.50 mg/L范围内与吸光度线性关系良好,相关系数r分别为0.9986,0.9943,0.9942。方法检出限铜为0.0067 mg/L,锌为0.0010 mg/L,铬为0.0014 mg/L,加标回收率为95.0%～105.7%。精密度试验验证铜、锌、铬的含量分别在0.01%～0.50%,0.01%～1.00%,0.01%～4.00%范围内重复性和再现性较好。此方法适合于红土镍矿中铜、锌、铬含量的测定。

Determination of Copper, Zinc and Chrome Content in Laterite Nickel Ores by Flame Atomic Absorption Spectrometry

The laterite nickel ore sample was decomposed with hydrochloric acid and nitric acid, the residue was melted with potassium pyrosulfate. Then in diluted hydrochloric acid medium, the content of copper, zinc and chrome was determined by flame atomic absorption spectrometry at 324.8,213.9, 357.9 nm, respectively. The background was deducted with deuterium lamp. Under optimized experimental conditions, the absorbance was linear with copper, zinc and chrome concentration in the range of 0.50-2.50 mg / L, 0.30-1.50 mg / L and 0.50-4.50 mg / L, respectively. The correlation coefficients were 0.998 6, 0.994 3, 0.994 2, respectively. The detection limits for Cu, Zn and Cr were 0.006 7,0.001 0,0.001 4 mg / L, respectively. The recoveries ranged from 95.0% to 105.7%. The repeatability and reproducibility were better as copper, zinc and chrome content range from 0.01% to 0.50%, 0.01% to 1.00%, 0.01% to 4.00%, respectively. This method was applicable for the determination of copper, zinc and chrome content in laterite nickel ore.