Thermophilic mineral bioleaching performance: A compromise between maximising mineral loading and maximising microbial growth and activity
Journal Article
2003
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The Journal of The South African Institute of Mining and Metallurgy
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Southern African Institute of Mining and Metallurgy
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University of Cape Town
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Abstract
Synopsis
Thermophilic bioleaching, conducted at temperatures in excess of
65°C, provides considerable benefit over mesophilic bioleaching,
particularly through extending the extent of leaching of base metal
minerals such as chalcopyrite. Thermophilic bioleaching is
facilitated through a group of micro-organisms known as the
Archae, well adapted to extreme environment. In order to maximize
the space time utilization of the stirred tank reactor in the
thermophilic bioleaching process, it is desirable to maximize the
loading of the finely divided mineral phase present while not
adversely affecting the microbial performance. In this paper, the
effect of the loading of the solid particulate phase on the
bioleaching performance of Sulfolobus metallicus was studied in a
stirred tank reactor. Emphasis was placed on the effect of the
concentration of the finely divided solid phase (35 – 75 µm). A
model system comprised of 3% (w/v) pyrite in the presence of
varying quantities of quartzite in the range 0 to 24% (w/v) was
used to obtain the different solids concentrations.
The bioleaching experiments revealed similar bioleaching
performance in the presence of 3 to 18% (w/v) total solids. Above
18% (w/v) total solids (15% quartzite loading), bioleaching was
impaired progressively with increasing solids concentration. At the
highest solids loading studied of 27% (w/v), bioleaching was still
observed. In terms of mass transfer, oxygen transfer potential was
not significantly influenced in the bioleaching process over the
range of solids investigated.
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Reference:
Sissing, A., & Harrison, S. T. L. (2003). Thermophilic mineral bioleaching performance: a compromise between maximizing mineral loading and maximizing microbial growth and activity. Journal of the south African institute of mining and metallurgy, 103(2), 139-142.