| 摘要 |
Copper values are efficiently recovered from a copper ore, including secondary sulfides, by first crushing the ore to a particle size P-80 of about 1 to 2 inches, then grinding the so crushed ore to a particle size P-80 of between Tyler 4 mesh and 20 mesh, and then classifying the ground ore into a fines fraction of less than 65 mesh and one or more coarse fractions of more than 65 mesh. The fines are then leached or subjected to flotation to form a concentrate which is leached to form a pregnant leach solution. In parallel, the coarse fraction or fractions are leached also to form a pregnant leach solution. The leaching operations are carried out with ferric sulfate lixiviant at atmospheric pressure and elevated temperature. During leaching ferric sulfate is reduced to ferrous sulfate. The pregnant leach solutions are then subjected to solvent extraction to recover the copper values and subsequently to electrowinning to produce copper metal. During the solvent extraction operation, free sulfuric acid is produced and is then used together with oxygen to oxidize the ferrous sulfate produced during the leaching steps back to ferric sulfate with is then re-used in the leaching of the fines and coarse fractions. |
