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1、BiominingBiomining & BioleachingContentsBrief introductionHistoryMicroorganismsProcessBenefitsBiomining & BioleachingBrief introductionBiomining is a broad term that describes the processing of metal containing ores and concentrates of metal containing ore using microbiological technology.Tw

2、o main process:Mineral bio-oxidationBioleachingalternatives to smelting, roasting, and pressure oxidationCodelcos Biomining PlantBiomining & BioleachingHistory166 A.D. the scientist Galen described “in situ” leaching in old copper and lead mine at Cyprus.1879 Bioleaching of low-grade ore at Rio

3、Tinto.1947 Thiobacillus ferrooxidans was identified and isolated from acid mine drainage.1965 Discovery of the first iron and sulfur oxidizing archaea Acidianus Brierleyi from thermal spring in Yellowstone.Biomining & BioleachingMicroorganismsFeatures:Single-celled and multiply by simple cell di

4、visionDerive energy by oxidizing iron and sulfurObtain carbon from carbon dioxideRequire oxygenRequire a sulphuric acid environment to growBiomining & BioleachingMicroorganismsClassification:The microbes can be conveniently grouped within temperature ranges at which they grow and where they are

5、found in the natural environment.Biomining & BioleachingMicroorganismsAmbient temperature bacteria:grow and function from 10C to 40C cylindrical-shapedabout 1 micrometer (m) long and 0.5 m in diameterE.g. Leptospirillum ferrooxidansAcidithiobacillus ferrooxidansBiomining & BioleachingMicroor

6、ganismsModerately-thermophilic bacteria 40-60C somewhat larger than mesophilesE.g.Acidithiobacillus caldusBiomining & BioleachingMicroorganismsExtremely thermophilic archaea 60-85C spherical shaped lack rigid cell wall; cell contents are enclosed by a membrane insteadE.g.Metallosphaera sedulaAci

7、dianus BrierleyiBiomining & BioleachingProcessBioleaching is mostly contact leaching.Biomining & BioleachingProcessGold extractionOreNumerous ferrous and sulphur oxidizing bacteria (Acidithiobacillus ferroxidans)1.Bacteria catalyzes the breakdown of the mineral arsenopyrite by oxidizing sulp

8、hur and metal and reducing dioxygen by H2 and Fe3+.Cell membraneThe electrons pass into the cell and are used in the biochemical processes to produce energy for the bacteria to reduce oxygen molecules to water.Biomining & BioleachingProcessGold extraction2. Bacteria oxidize Fe2+ to Fe3+Then they

9、 oxidize metal to higher positive oxidation state.With the electrons gained, they reduce Fe3+ to Fe2+ to continue the cycle.Gold is now separated from the ore into solution.Biomining & BioleachingBenefitsSimple and inexpensive process. Substantially lower capex and opex than in traditional smelting and refining processesNo sulfur dioxide emissions as in smeltersNo need for high p