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The Bioleaching of copper sulfide ores in saline media : shake flask studies Lo, Michael Joseph
Abstract
The feasibility of bioleaching two Chilean copper ores under saline conditions was evaluated by batch tests. Total copper content of the ores were 3.87% and 1.64%, respectively. Lower ore mineralogy was comprised of atacamite, chrysocolla, bornite, chalcopyrite, chalcocite, and minor pyrite, while Zaldivar's included brochantite, chrysocolla, chalcocite, and pyrite. Mixed bacterial cultures dominated by Thiobacillus ferrooxidans were used in all test work. As the effect of chloride ion on copper extraction was of primary concern, shake flask tests at various chloride levels were conducted. Sterile (no bacteria) tests were run under conditions identical to corresponding bioleach tests to provide information on abiotic leaching. All bioleach tests demonstrated, by attaining high Eh levels, that adaptation occurred at all chloride levels tested. On initial exposure to concentrations above baseline culture tolerance, inhibition occurred, manifesting as lengthier lag times, the severity increasing with the difference in chloride concentration between culture tolerance level and the level in the test medium. With repeated exposure to media containing identical chloride levels, lag times decreased, demonstrating further evidence of bacterial adaptation to chloride ion. Successful adaptation by bacteria was reflected by high copper extractions at all chloride levels for the bioleach tests, averaging 91.9% (Lower (CI) test series) and 94.5% (Zaldivar (CI) test series). As expected, the corresponding sterile tests did not achieve the same level of extraction, averaging 43.6% (Lower (CI)) and 82.0% (Zaldivar (CI)). Clearly, the Zaldivar ore was much more reactive to abiotic leaching than the Lower ore. While chloride-enhanced cupric-ion leaching was a factor for both sets of sterile tests, other factors may also have enhanced abiotic Zaldivar ore leaching. These factors are believed to include (a) conspicuous differences in mineralogical content and distribution, (b) apparently more acid-soluble copper mineralization, and (c) chloride-enhanced galvanic leaching.
Item Metadata
Title |
The Bioleaching of copper sulfide ores in saline media : shake flask studies
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
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Description |
The feasibility of bioleaching two Chilean copper ores under saline conditions was evaluated by
batch tests. Total copper content of the ores were 3.87% and 1.64%, respectively. Lower ore
mineralogy was comprised of atacamite, chrysocolla, bornite, chalcopyrite, chalcocite, and minor
pyrite, while Zaldivar's included brochantite, chrysocolla, chalcocite, and pyrite. Mixed bacterial
cultures dominated by Thiobacillus ferrooxidans were used in all test work.
As the effect of chloride ion on copper extraction was of primary concern, shake flask tests at
various chloride levels were conducted. Sterile (no bacteria) tests were run under conditions
identical to corresponding bioleach tests to provide information on abiotic leaching. All bioleach
tests demonstrated, by attaining high Eh levels, that adaptation occurred at all chloride levels
tested. On initial exposure to concentrations above baseline culture tolerance, inhibition occurred,
manifesting as lengthier lag times, the severity increasing with the difference in chloride concentration
between culture tolerance level and the level in the test medium. With repeated exposure
to media containing identical chloride levels, lag times decreased, demonstrating further evidence
of bacterial adaptation to chloride ion.
Successful adaptation by bacteria was reflected by high copper extractions at all chloride levels
for the bioleach tests, averaging 91.9% (Lower (CI) test series) and 94.5% (Zaldivar (CI) test
series). As expected, the corresponding sterile tests did not achieve the same level of extraction,
averaging 43.6% (Lower (CI)) and 82.0% (Zaldivar (CI)). Clearly, the Zaldivar ore was much
more reactive to abiotic leaching than the Lower ore. While chloride-enhanced cupric-ion leaching
was a factor for both sets of sterile tests, other factors may also have enhanced abiotic Zaldivar
ore leaching. These factors are believed to include (a) conspicuous differences in mineralogical
content and distribution, (b) apparently more acid-soluble copper mineralization, and (c)
chloride-enhanced galvanic leaching.
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Extent |
10495652 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-03-13
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0078604
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1996-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.