mineralization: chalcocite,covellite,molybdenite,in a quartz and feldspar.
This 40000 tpd concentrator is successfully floating copper at a coarser grind tha any of the mills surveyed(24 to 31% +65 mesh) yet produces one of the highest grade concentrates. Molybdenite recovery is based on the use of Nokes reagent as the copper depressant.
the mill flowsheet is essentially the sam as tha shown for El Salvador even though the grind employed is much coarser. Rougher concentrates are thickened and reground prior to two stage cleaning. A scavenger concentrate is floated from the cleaner tailings and returned to the regrind thickener with the scavenger tailings going to waste just as is done at El Salvador. Molbydenum recovery also follows El Salvador practice in that the cleaned copper concentrate is conditioned with P2S5 and NaOH (Nokes reagent) to depress seven times with a regrind of the No.2 cleaner concentrate and the final MoS2 flotation concentrate leached with NaCN to remove the residual copper. At the present time, the As2O3-Na2S reaction product is being tested at Chuquicamata as a replacement for P2S5-NaOH. The economics of this reagent are not yet known.