Chalcopyrite hydrometallurgy at atmospheric pressure: 1. Review of acidic sulfate, sulfate–chloride and sulfate–nitrate process options

• Comprehensive review of chalcopyrite hydrometallurgy in sulfate media
• Atmospheric pressure processes require catalysts, fine grinding or temperature.
• Stronger oxidants than ferric ions show future processing potential.
• Three predicted chalcopyrite surface structures may leach by different mechanisms.

The need to process low-grade and/or complex chalcopyrite-containing ores that cannot be concentrated is the main driver for the development of hydrometallurgical processes. The ferric sulfate–sulfuric acid system, with or without the assistance of microorganisms, has been studied extensively because it comprises the most promising, low-cost process route. Alternative oxidants to ferric ion are known but, as yet, their superior oxidation strengths have not been exploited other than at laboratory scale, probably due to their higher costs. Hybrid sulfate–chloride and sulfate–nitrate systems were included because they may offer specific advantages in some instances. The aims of this review were to summarise current knowledge in respect of these systems and highlight potentially rewarding areas for future research.