2008 Volume 49 Issue 11 Pages 2611-2617
Iron-oxide hosted copper-gold (IOCG) deposit is a newly recognized raw material for copper recovery. A poor understanding of its hydrometallurgical behavior has limited the development of its commercial practice for copper extraction. In this paper, the leaching behavior of IOCG ore in sulfuric acid medium containing hydrogen peroxide were studied in shaking flask and rolling-ball (RB) vessel. The dissolved copper and iron, pH and oxidation-reduction potential were monitored versus time. It was found that the IOCG ore is more difficult to leach than primary and secondary copper ores. Furthermore, some variables including sulfuric acid dosage, hydrogen peroxide addition and particle sizes were considered and investigated. The similar copper recovery was observed with the variation of the amount of sulfuric acid, and the addition of hydrogen peroxide did not enhance copper yield considerably. Although the higher copper recovery occurred with smaller particle sizes, the highest copper extraction was still not over 40% even for −0.02 mm size. The dissolved copper level behavior with time in shaking flask indicates the hindered dissolution is occurring. Moreover, more than 90% copper recovery in RB leaching confirmed the existing hindered dissolution in shaking flask. The passivation candidates of elemental sulfur was detected and confirmed by X-ray diffraction further, which were responsible for the low copper yield in shaking flask.