METHOD OF REPROCESSING MIDDLINGS-SOLUTIONS OF PLATINUM GROUP METAL AFFINAGE PROCESSES Russian patent published in 1998 - IPC

FIELD: precious metal metallurgy. SUBSTANCE: method can be used in affinage production of platinum group metals involving simultaneously occurring palladium and rhodium conversions. Method utilizes side product obtained in preparation of palladium from tetraamminopalladium chloride, mother solution from ammonia-mediated palladosammine precipitation step, to form reagent replacing ammonium chloride when precipitating rhodium ammonium-sodium hexanitrite in the process of rhodium affinage. Ammonium chloride solution substitute is prepared by treating above-mentioned mother solution to achieve pH value within the range from 1 to 5, separating salt precipitate, and optional evaporation of solution. When using reagent of invention, quality of final product does not worsen. EFFECT: reduced cost of affinage process. 2 cl, 2 tbl