Title: Microbiological leaching of chalcopyrite: an environmentally sound approach to processing a sulphide copper concentrate

Authors: A. Lopez Juarez, R.E. Rivera Santillan, N. Gutierrez Arenas

Addresses: Facultad de Quimica, Departamento de Ingenieria Metalurgica UNAM, Ciudad Universitaria Mexico DF 04510, Mexico. ' Facultad de Quimica, Departamento de Ingenieria Metalurgica UNAM, Ciudad Universitaria Mexico DF 04510, Mexico. ' Facultad de Quimica, Departamento de Ingenieria Metalurgica UNAM, Ciudad Universitaria Mexico DF 04510, Mexico

Abstract: Mineral sulphides are the main source of copper, from which this metal is recovered by pyrometallurgical processing after a flotation procedure. These processes generate high emissions of SO₂ gases, which, in many cases, are discharged into the environment. The bioleaching method had been successfully used in copper recovery from low grade and secondary sulphide ores. Only recently, has it begun to be used to recover copper from its original concentrates because it is an environmentally and economically attractive alternative for copper recovery. In this paper, the results obtained by bioleaching tests of a flotation concentrate using mesophile bacteria and thermophiles with two different catalytic ions are presented. At high temperatures (thermophiles), the extraction reaches 95% in 10 days, while at low temperatures (mesophile bacteria) the extraction only reaches 42% in about 3 months of experimentation.

Keywords: bioleaching; chalcopyrite; mesophile microorganisms; thermophiles; catalytic ions; microbiological leaching; sulphide copper concentrate; copper recovery; bacterial leaching; sulphur dioxide.

DOI: 10.1504/IJEP.2006.009110

International Journal of Environment and Pollution, 2006 Vol.26 No.1/2/3, pp.254 - 265

Published online: 02 Mar 2006 *

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