Microbial attachment to sulfide minerals in a bioleach environment

This research pertains to bioleaching of copper containing ores with particular reference to the copper sulfide mineral chalcopyrite (CuFeS₂). While it is focused on heap bioleaching, it has applications to stirred tank bioleaching operations. Industrial heap bioleaching offers opportunities for processing of low grade ores but poses process operational challenges. These challenges include ineffective heap inoculation, a lag period before effective leaching commences and poor heap performance. These aspects are attributed to several contributing factors, such as heap construction, engineering and microbial activity. To date little attention has been paid to colonisation as a means of mitigating these challenges and effectively improving process operation. Current literature regarding microbial attachment to sulfide minerals is limited to pure culture studies using iron oxidising mesophiles, and the use of sulfide mineral concentrates. In a heap environment, mineral dissolution is accelerated through the presence of a mixed consortium of microbial species; with the contribution of each not yet fully understood. In addition, gangue minerals comprise the bulk of the minerals present and thus cannot be neglected when attempting to better understand microbial attachment and the role of micro-organisms in a heap environment. The predominant methodology employed to study microbial attachment in a bioleach context has used batch agitated systems (shake flasks). This may not adequately represent attachment under heap-like fluid dynamics. The idea of this project stemmed from a requirement to contribute to the mitigation of challenges faced by industry through addressing the aforementioned gaps prevailing in literature and improving understanding of the role of microbial attachment and colonisation under conditions simulating a heap. The aim of this study was to investigate attachment of three bioleach micro-organisms (A. ferrooxidans, L. ferriphilum and S. metallicus)to complex, sulfide-containing minerals ores in a bioleach environment using methodologies simulating heap-like conditions.

Grantor dc:publisher.institution

Centre for Bioprocess Engineering Research

Year dc:date.issued

2009

Author dc:creator

• Africa, Cindy-Jade

Advisors dc:contributor.advisor

• Harrison, STL
• Van Hille, Rob

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/7702

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/7702