Core recently carried out an oxidative leach pilot plant to demonstrate copper recovery from a low grade chalcopyrite concentrate.  The project investigated hydrometallurgical options for recovery of copper in flotation tailings, that would be sent to the tailings dam from a copper processing circuit. Precipitated copper oxide products generated from the piloted leach process are to be blended back into the primary copper concentrate generated by the flotation plant.

Copper Recovery from a Low Grade Tailings Stream

Batch testwork at a 10 L and smaller scale was carried out ahead of the pilot programme to define design parameters for the pilot plant. A complete pilot design package was developed to support the pilot programme.

The pilot programme treated 250 kg of flotation concentrate during a 15 day period of continuous operation. Batch ultrafine grinding of concentrate to P80 ~10 µm was conducted as required during the pilot campaign. A customised leach feed system enabled a low slurry feed rate of 1.5 kg/h to a train of oxidative leach tanks followed by a train of pH-controlled neutralisation tanks. Neutralisation removed 99%+ of iron from the leach liquor. Discharge slurry was filtered and washed through Core’s digitally controlled pilot filtration tanks, with the pregnant leach solution advancing to a train of pH-controlled metal recovery (precipitation) tanks. A slurry of mixed copper oxide product was generated, and downstream testing on product quality carried out.

The pilot programme successfully demonstrated 95%+ copper recovery from the concentrate, and generated a 40%+ Cu product.

Key to this programmes success were:

  • The involvement of Core’s engineers in the operation of the pilot to provide sophisticated analysis and correction of process performance during critical periods of the plant’s operation.
  • Core’s experience in operating low feed rate hydrometallurgical pilot plants that generate data of sufficient quality for engineering and due-diligence requirements.
  • The dedication and quality of Core’s technical staff working closely with plant management staff to ensure process conditions were strictly adhered to.

  • Core having an extensive array of equipment necessary for the design and mobilisation of the pilot plant.
  • Core’s on site laboratory providing fast turnaround and high quality analysis of process streams.