Abstract: An improved hydrometallurgical process for extracting metals from ocean-mined ferromanganese nodules. The process includes the steps of contacting the ferromanganese nodules in an extraction zone with an aqueous solution containing effective amounts of chloride ions and nitrate ions necessary to displace metal values in the ore at an elevated temperature and continuing the contact to form an extraction mixture slurry including a liquid component comprising an aqueous solution containing extracted metal values from the ferromanganese nodules dissolved therein and a solid tailing component; and, separating the liquid and solid components of the extraction mixture slurry.