铅试金-火焰原子吸收光谱法测定废旧电机中钯

废旧电机中贵金属钯的准确测定,对废旧电机的综合回收利用具有十分重要的意义。废旧电机中钯含量较低,且还含有大量的铜,若直接酸溶测定钯,基体干扰较为严重。实验选用铅试金法对废旧电机样品中的钯进行分离富集,使用空气-乙炔火焰,以247.6 nm为测定波长,建立了火焰原子吸收光谱法(FAAS)测定废旧电机中钯的方法。对氧化铅用量、灰吹温度、测定介质进行了优化,确定了氧化铅用量为200 g,灰吹温度为900 ℃,测定介质为10%(体积分数)盐酸。干扰试验表明,样品中的铅、铋、碲和银在单独或混合存在时均不会对钯的测定产生影响。校准曲线线性范围为1.00~4.00 μg/mL,相关系数为0.999 92;方法检出限为0.051 8 μg/mL,定量限为0.173 μg/mL。采用实验方法测定废旧电机中的钯,结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,相对标准偏差(RSD,n=7)为2.2%～3.1%,加标回收率为98%～102%。

Determination of palladium in waste motor by flame atomic absorption spectrometry with lead fire assay

The accurate determination of precious metal palladium in waste motors is of great significance to the comprehensive recycling of waste motors. The content of palladium in the waste motor is relatively low, and it also contains a large amount of copper. If the content of palladium is directly determined after acid dissolution, the matrix interference will be serious. In experiments, the lead fire assaying method was used for the separation and enrichment of palladium in waste motor samples. The method for determination of palladium in waste motors by flame atomic absorption spectrometry (FAAS) was established using air-acetylene flame. The determination wavelength was 247.6 nm.The amount of lead oxide, the cupellation temperature, and the measurement medium were optimized: the amount of lead oxide was 200 g, the cupellation temperature was 900 ℃, and the measurement medium was 10% (volume fraction) hydrochloric acid. The interference tests showed that the single presence or coexistence of lead, bismuth, tellurium and silver in sample will not affect the determination of palladium. The linear range of calibration curve was 1.00-4.00 μg/mL, and the correlation coefficient was 0.999 92. The limit of detection was 0.051 8 μg/mL, and the limit of quantification was 0.173 μg/mL. The content of palladium in waste motor was determined according to the experimental method, and the found results were basically consistent with those obtained by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The relative standard deviations (RSD, n=7) were between 2.2% and 3.1%, and the recoveries were between 98% and 102%.