bacterial leaching

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BACTERIAL LEACHINGKustiarana Willyandhika 3334090855

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OUTLINEPREFACE

BACTERIAL LEACHING HISTORYPRINCIPLE OF BACTERIAL LEACHING

MECHANISM OF BACTERIA ACTIONKINETIC S ASPECT APPLICATION CONCLUSION REFERENCE2

PREFACEWhat is Bacterial Leaching?

Bacterial Leaching is the extraction of metals from ores using the principal components of water, air and bacteria

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KIND OF BACTERIAWhat kind of Bacteria devided into two bacteria used to classes bacterial leaching??

Autotrophic

Heterotrophic

Organisms that live on inorganic matter

Organisms that live on organic matter4

WHY BACTERIAL LEACHING?

Comparative rate of copper extraction from chalcopyrite with bacterial and sterile solutionBacterial leaching is possible with low concentrations ores and requires little energy inputs5

BACTERIAL LEACHING HISTORY1.

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1887, Winorgradasky : bacteria able to oxidize elemental sulfur to sulfuric acid 1951, Colmet and Hinkle : bacteria as Thiobacillus ferroxidans 1963, Ruzzell and Trussell : leaching operation in Rio Tinto, Spain, used bacteria Then, T. Ferroxidans involved in many leaching operation in other place6

PRINCIPLE OF BACTERIAL LEACHINGAcidolisys is a chemical reaction involving the decomposition of a molecule, with the addition of the elements of an acid to the molecule. The reaction is comparable to hydrolysis or alcoholysis, in which water or alcohol, respectively, is used in place of the acid. Also known as acyl exchange. Complexolysis is a process corresponding to microbial formation of complexing or chelating agents that solubilize metal ions. As a resultof that metal-organic complexes or metal-organic chelates are formed. The chelating compunds formed by microorganisms are organic acids Redoxolysis is the oxidation and reduction reactions. Organic acidmediated solubilization, where oxalic acid can effect the reduction of metal ions. Sulfuric acid is the main inorganic acid found in leaching environments. It is formed by thiobacilli7

MECHANISM OF BACTERIA ACTIONBacterial Leaching process

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MECHANISM OF BACTERIA ACTIONA generalised reaction can be used to express the biological oxidation of a mineral sulphide involved in bacterial leaching: MS + 2O2 MSO4 where M is a bivalent metal

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MECHANISM OF BACTERIA ACTIONThere are two major mechanisms of bacterial leaching1.

2.

the first mechanism is direct leaching, in the process in direct leaching metal sulphides can be directly oxidised by T. ferrooxidans to soluble metals sulphates the second mechanism is indirect leaching, the microbial action results in the oxidation of ferrous ions (Fe2+) to ferric ions (Fe3+) and the ferric ions then chemically oxidise the sulphide minerals10

MECHANISM OF BACTERIA ACTION

However, the model of direct and indirect metal leaching is still under discussion11

THE KINETICS OF LEACHING REACTIONSBoth the kinetics and the final metal recoveries depend on the mineralogical type of the ore (Tzeferis and Agatzini-Leonardou, 1994). The difficulty in mobilizing metals, exp. nickel, from various minerals phases is different and this difference is generally reflected on the leaching effectiveness (Tzeferis and AgatziniLeonardou, 1994)

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APPLICATION

The Mintek-NICICO chalcopyrite copper heap bioleach demonstration plant at the Sarcheshmeh Copper Complex, located in the province of Kerman, Iran13

APPLICATIONBacTech Mining Corporation Toronto, Ontario, Canada BacTech Mining Corporation Process

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CONCLUSION1.

2.

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Bacterial leaching is a revolutionary technique used to extract various metals from their ores. Another methods of extraction such smelting are very energy intensive and require high concentration of elements in ores. Bacterial leaching is possible with low concentrations ore and requires little energy inputs

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REFERENCE

Habashi, Fathi. 1970. Principle of Extractive Metallurgy volume 2. Gordon and breach: New York Jonglertjunya, Woranart. 2003. Bioleaching of chalcopyrite. Doctor Thesis, The University of Birmingham Brandl, Helmut. Microbial Leaching of Metals. Zrich, Switzerland16

THANK YOU17