Migration of platinum, palladium, and gold in the water systems of platinum deposits

Abstract

In order to explore the behavior of platinum group elements in the ecosystems of mineral deposits, the migration characteristics of platinum and palladium were determined in the pH range typical of surface waters. Model sorption experiments on the precipitation of platinum and palladium on iron oxyhydroxide in the presence of major natural inorganic and organic ligands showed that platinum interacts most actively with an iron oxyhydroxide (ferrihydrite) precipitate within the whole pH range, both in the absence and presence of natural organic substances, whereas palladium is preferentially bound to dissolved, suspended, and sedimentary humic substances. The thermodynamic calculation of coexisting platinum and palladium species is qualitatively consistent with experimental data on the character of accumulation and migration of these elements. The obtained data suggest that the migration of platinum and palladium into highly colored waters in the zones of platinum group element deposits results in their extensive deposition on natural geochemical barriers.