Abstract: There is provided a hydrometallurgical process of recovering rhenium values from mixtures thereof with other metal values in which the rhenium values constitute a minority amount, for example super-alloys, which comprises subjecting the mixture to strongly oxidizing acid conditions, preferably an aqueous mixture of hydrochloric acid and nitric acid, so as to form perrhenate species of at least the major proportion of the rhenium values in the mixture, dissolving the perrhenate species and other soluble metal species in aqueous solution, removing insoluble metal species from the aqueous solution, and isolating the rhenium species from the solution.