Metal recovery by leaching agglomerates of metal-containing material/pyrite
A method of recovering a metal, such as copper or nickel or zinc or cobalt, from a metal-containing material, such as a metal-containing material that has been categorized by a mine operator as being “non-economic” from the perspective of recovering the metal from the material. Mixing (i) the metal-containing material and (ii) pyrite and forming agglomerates. Leaching agglomerates with a leach liquor, with pyrite generating acid and heat that facilitate recovering the metal from the metal-containing material, and forming a pregnant leach liquor containing metal. Recovering the metal from the pregnant leach liquor.
1. A method of recovering copper from a low-grade copper-containing material comprising the steps of:
(a) obtaining a pyrite-containing slurry from a mine;
(b) mixing (i) the low-grade copper-containing material and (ii) pyrite in, or obtained from, the pyrite-containing slurry and forming agglomerates;
(c) heap leaching agglomerates from step (b) with a leach liquor and microbes, with pyrite generating acid and heat that facilitate recovering copper from the low-grade copper-containing material, and with the microbes oxidising ferrous iron to ferric iron, and forming a pregnant leach liquor containing copper; and
(d) recovering copper in solution from the pregnant leach liquor.
2. The method defined in claim 1 wherein the low-grade copper-containing material is in the form of as-mined material or stockpiled material.
3. The method defined in claim 2 further includes comminuting as-mined or as-stockpiled material.
4. The method defined in claim 3 wherein comminuting further includes crushing as-mined or as-stockpiled material in one or more than one comminution circuit that reduces the size of the as-mined or as-stockpiled material.
5. The method defined in claim 4 wherein crushing further includes crushing as-mined or as-stockpiled material successively in primary, secondary and tertiary comminution circuits.
6. The method defined in claim 1 further comprising mixing the low-grade copper-containing material and the pyrite-containing slurry in step (b).
7. The method defined in claim 1 wherein the method includes, prior to step (b), removing pyrite from the pyrite-containing slurry.
8. The method defined in claim 7 wherein removing pyrite from the pyrite-containing slurry further includes producing pyrite in a concentrate form.
9. The method defined in claim 7 wherein removing pyrite from the pyrite-containing slurry forms (i) a pyrite-containing material and (ii) an inert stream.
10. The method defined in claim 1 wherein the mixing is carried out before forming agglomerates in step (b).
11. The method defined in claim 1 wherein mixing and forming agglomerates are carried out simultaneously in step (b).