COPPER LEACHING PROCESS

摘要

13485:RDS COPPER LEACHING PROCESS A technique is provided for leaching copper from copper ore in which the ore is crushed to a maximum particle size small enough to expose a major proportion of the copper minerals in the ore. Crushed ore is wetted with separate additions of water and concentrated sulfuric acid and agglomerated to form lumps with apparent diameters about the same as the maximum particle size of the ore. The quantity of acid is 50 to 120% of the quantity needed to react stoichiometrically with all the copper in the ore. The agglomerated copper ore is aged to indurate the agglomerate lumps and solubilize copper. A leach liquid containing a low concentration of sulfuric acid is percolated through such a layer of indurated lumps for producing a pregnant leach liquid from which copper is recovered. Aqueous raffinate from copper recovery is recycled as leach liquid. When copper is recovered by solvent extraction the quantity of acid in the leach liquid is about the same as the quantity added by solvent extraction. When the copper is recovered by cementation the quantity of acid in the leach liquid is about 130% of the quantity needed to react stoichiometrically with copper remaining in the ore after subtracting the portion made water soluble by aging. If desired, ferrous ion in the raffinate can be oxidized to ferric ion before percolating such raffinate through an ore layer for leaching sulfide minerals.