Document Detail

Silicate mineral dissolution during heap bioleaching.
MedLine Citation:
PMID:  17705245     Owner:  NLM     Status:  MEDLINE    
Silicate minerals are present in association with metal sulfides in ores and their dissolution occurs when the sulfide minerals are bioleached in heaps for metal recovery. It has previously been suggested that silicate mineral dissolution can affect mineral bioleaching by acid consumption, release of trace elements, and increasing the viscosity of the leach solution. In this study, the effect of silicates present in three separate samples in conjunction with chalcopyrite and a complex multi-metal sulfide ore on heap bioleaching was evaluated in column bioreactors. Fe(2+) oxidation was inhibited in columns containing chalcopyrite samples A and C that leached 1.79 and 1.11 mM fluoride, respectively but not in sample B that contained 0.14 mM fluoride. Microbial Fe(2+) oxidation inhibition experiments containing elevated fluoride concentrations and measurements of fluoride release from the chalcopyrite ores supported that inhibition of Fe(2+) oxidation during column leaching of two of the chalcopyrite ores was due to fluoride toxicity. Column bioleaching of the complex sulfide ore was carried out at various temperatures (7-50 degrees C) and pH values (1.5-3.0). Column leaching at pH 1.5 and 2.0 resulted in increased acid consumption rates and silicate dissolution such that it became difficult to filter the leach solutions and for the leach liquor to percolate through the column. However, column temperature (at pH 2.5) only had a minor effect on the acid consumption and silicate dissolution rates. This study demonstrates the potential negative impact of silicate mineral dissolution on heap bioleaching by microbial inhibition and liquid flow.
Mark Dopson; Anna-Kaisa Halinen; Nelli Rahunen; Dan Boström; Jan-Eric Sundkvist; Marja Riekkola-Vanhanen; Anna H Kaksonen; Jaakko A Puhakka
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biotechnology and bioengineering     Volume:  99     ISSN:  1097-0290     ISO Abbreviation:  Biotechnol. Bioeng.     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-01-31     Completed Date:  2008-02-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7502021     Medline TA:  Biotechnol Bioeng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  811-20     Citation Subset:  IM    
Copyright Information:
Copyright 2007 Wiley Periodicals, Inc.
Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.
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MeSH Terms
Bioreactors / microbiology*
Minerals / chemistry*,  metabolism*
Silicates / chemistry*,  metabolism*
Soil / analysis*
Soil Microbiology*
Reg. No./Substance:
0/Minerals; 0/Silicates; 0/Soil

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