Development of a support analysis for the production of dispersoid stabilized platin compounds

Platin metal for the production of special glasses need to be purified from side metals like Rhodium, Iridium and Palladium by different chemical and physical separation steps to gain the appropriate glass quality. In order to control the quality of the different steps for separating disturbing platin side metals from the main platin matrix, an analytical method is necessary. The main scope of the thesis was the development of an efficient and reliable methodology for the determination of Pt, Pd, Rh and Ir concentrations in the mayor products of the recycling process. UV/Vis spectroscopy was chosen, because a broad area of selective reagent can be used to obtain selective and fast results with the detection limit required. The determination of platin is based on a 1m SnC12 solution in 3,5 n HCI. The spectrum shows the main absorption at 402 nm. Palladium can be determined by p-nitrosodimethylanilin in an ethanolic solution. The absorption occurs at a wavelength of 525 nm. SnC12/HBr in a weak acidic solution is used for the detection of rhodium. The spectrum shows a clear peak at 427 nm. Iridium in acidic solution shows an absorption maximum at 488 nm without further preparation of the sample. The amount of platin in real samples exceeds the concentration of the accompanied side metals Rh, Ir, and Pd tremendously. Hence the platin matrix has to be eliminated before analysis of the side metals can occur. The elimination of the platin matrix was accomplished by an adapted gravimetric separation method, which is based on the usage of NaBrO3 solution at pH 8. At such conditions, platin will be separated from the other platin metals quantitatively. The methods were optimized by the variation of temperatures, pH and reagent concentration. The whole method based on the elimination of platin and usage of the above described selective reagents was tested at different real samples and the results were compared to ICP AES results obtained from the same samples. (author)