Investigation of an indigenous chalcopyrite ore leaching in ammonia solution: characterization, leaching and kinetics

ABSTRACT

Chalcopyrite ore is one of the most abundant and pertinent oxidized copper minerals. In this research, the dissolution kinetics of chalcopyrite in an ammonia solution was examined. During leaching, the influences of leachant concentration, temperature, and particle diameter on the extent of copper ore dissolution were investigated. However, it was affirmed that the dissolution efficiency of chalcopyrite ore increased with decreasing particle fraction and increasing reaction temperature and ammonia concentration. About 68.6% copper ore dissolution was achieved with 2.0 mol/L NH₃, 75 ºC reaction temperature, and 45 μm particle diameter within 120 minutes. The dissolution reaction mechanism was found to be described by diffusion-control with a calculated activation energy of 32.26 kJ/mol. In the XRD spectra of the residual product obtained at established conditions, CuFeS₂ peaks were absent, indicating the leachability of the sample. Hence, the leach residue could serve as an important by-product for some local industries.

KEYWORDS:

• Chalcopyrite ore
• sulfidic minerals
• ammonia
• characterization
• leaching
• kinetics

Acknowledgments

The authors gratefully acknowledge Miranda Waldron of the Centre for Imaging & Analysis, University of Cape Town, South Africa for assisting with SEM & EDX analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).