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8/15/2019 Biomining Presentation
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Bioleaching/BiocorrosionBioleaching/Biocorrosion
Metals/BiominingMetals/Biomining
Lisa Smith
Marian Cummins
Deborah Mc Auliffe
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• Metal Contamination of soil environments
and the assessment of its potential risk to
terrestrial environments and human health
is one of the most challenging tasksconfronting scientists today.
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• Challenge for mining companies – Serviceno long term impact on environment
• !ncreasing interest in microbial approachesfor recovery of base and precious metals
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"iomining"iomining
• #se of microorganisms
– $res of high %uality rapidly being depleted
– &nvironmentally friendly alternative
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"iomining"iomining
• 'aturally e(isting microorganisms leach
and o(idate
). "ioleaching
*. "ioo(idation
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• "ioleaching
– &(traction of metals +ith the use of
microorganisms
• "ioo(idation
– Microorganisms make metal ready for
e(traction
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,eneral -roperties,eneral -roperties
• Chemolithotrophic rock eating/
• Autotrophic
• Acidophilic 0 acid loving1
• #se o(ygen as the preferred electron acceptor
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Specific MicroorganismsSpecific Microorganisms
Most common2
• Thiobacillus ferrooxidans
• Thiobacillus thiooxidans
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Thiobacillus ferrooxidansThiobacillus ferrooxidans
• 3od shaped
• 3elatively %uick gro+ing
• ,ram negative
• Strictly aerobic• Aerobic conditions uses 4e*5 or reduced S 0S*1 as
electron acceptor
• Ano(ic conditions use 4e65 as electron acceptor
• Mod. 7hermophilic8 temperatures of *96: degree C andp; of *.9
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Thiobacillus thioxidansThiobacillus thioxidans
•
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7he -rocess7he -rocess
• * Methods Direct and indirect
• Direct en>ymatic attack and occurs at the
cell membrane
• !ndirect bacteria produce 4e65 0 ferric iron1
by o(idi>ing 4e*5 0ferrous iron1
• 4e65
is a po+erful o(idi>ing agent thatreacts +ith the metals and so produces
4e*5 in a continuous cycle.
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Copper -rocessCopper -rocess
• *:? Copper production is recovered by
biomining
• MS 5 *$* MS$@
• Metal sulphide is insoluble and metal sulphate is
usually +ater soluble
• Cu ore contains CuS and Cu4eS*
• T. ferrooxidans brings about both direct andindirect o(idation of CuS via the generation of
04e651 ferric iron from 04e*51 ferrous sulphate
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• Cu is recovered by solvent e(traction or by
using scrap iron +here the iron replaces
the Cu
• CuS$@
5 4e Cu 5 4eS$@
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$ther Application of "iomining$ther Application of "iomining
• ,old
• Due to depletions by the )B9=s
• Dependent on lo+er grade ore
• ,old is encased in the sulphide minerals• T. ferrooxidans
• 4airvie+ mine in S. Africa
• 3ecovery rate of 9? to :?
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Cont=dCont=d
• -hosphates industry
• *nd largest agriculture chemical
• :.: million tons year in the #S
• 7raditional method +as burning at high temperatures0solid phosphorus1 or +ith ;* S$@0phosphoric acid and
gypsum1
• Pseudomonas cepacia E37 and Erwinia herbicola
• ,lucose gluconic and * ketogluconic acid• &nvironmentally friendly as no ;s S$@ re%uired and it
occurs at room temperature.
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Case Studies
5
&conomics of "iomining
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Microbes E7$ 7ACFL& M!'&Microbes E7$ 7ACFL& M!'&
GAS7&=GAS7&=
• Scientists are using microbes to clean up theproblem of corrosive acid pollution left over asmining +aste
• Some of the microbes being used +ere found in America8 Gales and the Caribbean island
• "y discovering microbes +hich can survive inthis environment8 +ill help address seriousenvironmental ha>ards at abandoned mines andsoil heaps
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!ndustrial "iotechnology "iomining!ndustrial "iotechnology "iomining
• Commercial Capabilities
• #nderpinning &(isting Capabilities
• &merging Capabilities
• !nstitutional Capabilities
• Fno+ledge Skills
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Chile "iomining -rogramChile "iomining -rogram
• Gorlds first biggest producer of Copper
• !n )) copper mines +ere nationali>ed
• "ut in )9 Chile returned to democracy
• Started in )9 +ith target H*.:m tons for theyear *999
• 7his 4igure +as superseded in ): andproduction e(ceeded :m tons late )9=s
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&conomic Study of the Canadian&conomic Study of the Canadian
"iotechnology"iotechnology
• Canadian environmental I industrial
biotechnology firms
• Microorganisms in applications such as
bioremediation leaching8 energy production
• Canadian Stakeholders +ithJ #.S8
&uropean8 Kapanese environmental
regulators
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"iomining"iomining7here=s ,$LD in them thar= -lants/7here=s ,$LD in them thar= -lants/
• ,old rush miners might have been better
off using plants to find gold rather than
panning streams for precious metal
• &arly prospectors in &urope used certain
+eeds as indicator plants that signaled the
presence of metal ore
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3emediation3emediation
• 3esponse to human health effects
• 3esponse to environmental effects
• 3edevelopment
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"ioremediation"ioremediation
• Destroys or renders harmless various
contaminants using microbial activity
• "ioremediation of metalcontaminated soil
– Soil 4lushing
– Soil Gashing
– -hytostabili>ation
– -hytoremediation
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-hytostabili>ation-hytostabili>ation
• !mmobili>ation of a contaminant in soilthrough – Absorption I Accumulation
– Adsorption – -recipitation
• Also use of plant I plant root to prevent
contaminant migration• Soil is then farmed to improve gro+th and
reduce mobility and to(icity of contaminant
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-hytoremediation-hytoremediation
• #se of plants to remove contaminants
from soil
• Certain plant speciesmetal
hyperaccumulators
– e(tract metals8 concentrate them in their
leaves
• -revent recontaminationplants harvested
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• Leaves accumulate
metals and are
harvested
• 3oots take up metals
from contaminated
soil and transport to
the stem8 leaves
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"iomining"iomining5Carried out insitu
5Less energy input
5'o to(icno(ious gases produced
5'o noise or dust problems
5-rocess is self generating
5Large or small scale operations
5Gide variety of metals 0Cu8 Ag8 -b8 Au8 n1
5Gork on lo+ grade ores
Slo+ process
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Traditional extraction causes
environmental problems and
degradation, biomining offers an
environmentally friendly alternative!!!!!!