Abstract: The process comprises the steps of leaching the concentrate with hot hydrochloric acid and chlorine gas to dissolve most of the gold, platinum and palladium, treating the residue from the leaching step with an excess of an alkaline oxidizing agent to solubilize the ruthenium, slurrying the resulting solids in water, combining the precious metal values from the slurry with the liquor from the leaching step and releaching the resulting slurry with hot hydrochloric acid and chlorine. The leach liquor which is then separated from the remaining solids is a chloride solution which contains substantially all the platinum group metals and gold present in the concentrate.

Abstract: A process for sequentially and selectively separating gold and platinum group metals from aqueous solutions containing them is disclosed.First, ruthenium and osmium are oxidized to their tetroxides and then removed from the solution. Then, gold is removed by solvent extraction preferably with dibutyl carbitol. Next, palladium and platinum are removed by solvent extraction with an alkyl sulphide and tributyl phosphate respectively, care being taken to reduce iridium in solution before platinum extraction to prevent it extracting with the platinum. Then the iridium is reoxidized and removed from solution. Finally, rhodium is removed from the solution.Using this process gold, platinum and palladium of saleable purity can be extracted directly without the need for further refining steps.