Thermophilic Heap Leaching of a Chalcopyrite Concentrate

Petersen, J; Dixon, D G

Thermophilic Heap Leaching of a Chalcopyrite Concentrate

Journal Article

2002

Journal Title

Minerals Engineering

Link to Journal

http://www.sciencedirect.com/science/journal/08926875

Publisher

Elsevier

Publisher

University of Cape Town

License

http://creativecommons.org/licenses/by-nc-nd/4.0/

Abstract

Thermophiles have been shown to be the only micro-organisms to leach chalcopyrite successfully. Heap leaching may be a feasible alternative to conventional bio-reactors, providing a high temperature environment can be maintained within the heap without external heating. In the present study thermophilic heap leaching of a chalcopyrite concentrate coated onto inert support rocks (the GEOCOAT™ process) was studied in sets of small heated columns. The temperature was gradually increased to 70 °C, while successively introducing various mesophile and thermophile cultures. Individual columns were dismantled after progressively longer leach periods and the residual concentrates analysed. Copper extractions in excess of 90% were achieved within 100 days. On the basis of head and residue analyses the rate of reaction heat generated was calculated. A comprehensive heap heat conservation model was used to determine whether the experimental temperatures can be achieved and maintained in a full scale heap. Results indicate that operating hot heaps successfully is possible within a certain range of process parameters.