Abstract:Platinum and palladium are important precious metals, which are often recovered in the process of electrolytic silver. In the process of producing silver products, a smelting enterprise needs to determine platinum and palladium in high-silver nitric acid decomposition solution and palladium precipitation solution. Inductively coupled plasma optical emission spectrometry (ICP-OES ) has the advantages of high sensitivity, low detection limit, wide linear range, simultaneous detection of multiple elements, rapid and accurate, and has been widely used in recent years. However, the method to the determination of platinum and palladium in nitric acid decomposition solution and palladium precipitation solution has not been applied in the present literature. In this paper, ICP-OES method was used to determine platinum and palladium in high-silver nitric acid decomposition solution and palladium precipitation solution. The results of high-silver matrix interference test, organic palladium precipitation agent interference test, fire assay enrichment test and different acid media tests were compared. The following conclusions are drawn. The silver matrix interference phenomenon is not obvious, and there is no need to separate the silver matrix. The organic palladium precipitation agent has no interference on the determination results. The viscosity of sulfuric acid makes the determination results deviate, and the best digestion method should be nitric acid system digestion. The results of the fire assay enrichment method is 30% lower for palladium and 38% lower for platinum, and the loss is large. Platinum and palladium in high-silver nitric acid decomposition solution and palladium precipitation solution were determined by ICP-OES method after digestion with nitric acid system, and the recovery rate was within 95%-105%, and the relative standard deviation was less than 5%, which were stable and reliable. The test shows that the method is convenient to operate and has strong practicability. It can be used for actual analysis of platinum and palladium in high-silver nitric acid decomposition solution and palladium precipitation solution.
