Oxidation process for releasing metal values in which nitric acid is regenerated in situ

A process for oxidizing an ore, comprising:

• continuously reacting the crushed ore suspended as a slurry in aqueous nitric acid in the presence of oxygen, thereby oxidizing the ore and generating nitrogen oxides, wherein the crushed ore and aqueous nitric acid are continuously introduced into a first end of a covered reaction vessel, and oxygen is continuously introduced into the vessel and gas is continuously removed therefrom, said vessel having a plurality of internal partitions spaced from one another defining a plurality of cells within the vessel, said partitions having apertures therein providing a pathway for the flow of the gas and slurry phases through the vessel, and each cell having means for agitating the slurry;
• continuously agitating the slurry in each cell to maintain the ore particles in suspension in the aqueous acid and to provide a discontinuous liquid phase in the nitrogen oxides containing gas flowing therethrough, so that nitric acid is regenerated;
• flowing the slurry and gas phases through the reaction vessel from cell to cell at rates which allow the ore to be sufficiently oxidized to enable the recovery of the metal of interest by conventional means;
• and
• continuously removing slurry from a second end of the vessel.