锍镍试金-电感耦合等离子体质谱法测定分金渣中铑和铱

建立测定分金渣中铑和铱含量的检测方法,对实现分金渣中铑和铱的有效提取、铑和铱冶炼新工艺开发及提高铜阳极泥的综合回收利用率具有重大意义.分金渣经锍镍试金预处理,用6 mol/L盐酸溶解锍镍扣使得含铑和铱的沉淀与其他杂质元素分离,趁热过滤,沉淀经王水(1+1)密封消解,以103Rh和193 Ir为测定同位素,实现了电感耦合...

Determination of rhodium and iridium in gold residue by inductively coupled plasma mass spectrometry with nickel sulfide fire assay

The establishment of determination method for the contents of rhodium and iridium in gold residue was of great significance for the effective extraction of rhodium and iridium from gold residue, the development of new smelting process for rhodium and iridium, and the improvement of comprehensive recovery and utilization of copper anode slime. The gold residue was pretreated by nickel sulfide fire assay, and the nickel matte buckle was dissolved with 6 mol/L hydrochloric acid to separate the precipitates of rhodium and iridium from other impurity elements. The solution was filtered while it was hot, and the precipitates were digested by aqua regia (1+1) in closed system. The determination of rhodium and iridium in gold residue by inductively coupled plasma mass spectrometry (ICP-MS) was realized with ¹⁰³Rh and ¹⁹³Ir as the determination isotopes. The experimental conditions were investigated, including the ingredient of nickel sulfide fire assay, the concentration of hydrochloric acid for dissolution of nickel matte buckle, the closed digestion temperature and time. The possible mass spectral interference was eliminated by selecting the suitable determination isotopes. ¹⁸⁵Re and ²⁰³Tl were selected as the internal standard of ¹⁰³Rh and ¹⁹³Ir, respectively, which eliminated the influence of signal drift. A series of mixed standard solution of rhodium and iridium were determined under the optimized experimental conditions. The results showed that the mass concentration of rhodium and iridium in range of 10-50 μg/L were linear to the ratio of corresponding intensity of rhodium and iridium to the internal standard. The linear correlation coefficients of calibration curves were higher than 0.999. The limit of detection of this method was 0.58 μg/L and 0.035 μg/L, respectively. The limit of quantification was 1.74 μg/L and 0.11 μg/L, respectively. The contents of rhodium and iridium in six gold residue samples were determined according to the experimental method. The relative standard deviation (RSDs, n=7) of determination results were between 1.7% and 4.9%, and the recoveries were in range of 90%-103%. According to the actual phase composition and the contents of rhodium and iridium in gold residue, the simulation samples were prepared with gold powder (w_Au>99.99%), silver powder (w_Ag>99.99%), platinum powder (sponge platinum, w_Pt>99.97%),palladium powder(sponge palladium, w_Pd>99.97%), rhodium powder (sponge rhodium, w_Rh>99.97%) and iridium powder (sponge iridium, w_Ir>99.97%) after grinding and uniform mixing. The contents of rhodium and iridium in gold residue simulation samples were determined according the experimental method, and the results were consistent with the theoretical values.