Download - Bacterial Leaching

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Kustiarana Willyandhika3334090855

BACTERIAL LEACHING

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OUTLINEPREFACE

PRINCIPLE OF BACTERIAL LEACHING

KINETIC S ASPECT

APPLICATION

REFERENCE

CONCLUSION

BACTERIAL LEACHING HISTORY

MECHANISM OF BACTERIA ACTION

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PREFACE

What 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 BACTERIA

Bacteria devided into two classes

Autotrophic Heterotrophic

Organisms that live on inorganic matter

Organisms that live on organic matter

What kind of bacteria used to

bacterial leaching??

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WHY BACTERIAL LEACHING?

Comparative rate of copper extraction from chalcopyrite with bacterial and sterile solution

Bacterial leaching is possible with low concentrations ores and requires little energy inputs

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BACTERIAL LEACHING HISTORY

1. 1887, Winorgradasky : bacteria able to oxidize elemental sulfur to sulfuric acid

2. 1951, Colmet and Hinkle : bacteria as Thiobacillus ferroxidans

3. 1963, Ruzzell and Trussell : leaching operation in Rio Tinto, Spain, used bacteria

4. Then, T. Ferroxidans involved in many leaching operation in other place

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 acid-mediated 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 thiobacilli

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Bacterial Leaching process


A 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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There are two major mechanisms of bacterial leaching

1. 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

2. 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 minerals

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However, the model of “direct” and “indirect”metal leaching is still under discussion

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THE KINETICS OF LEACHING REACTIONS

Both 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 Agatzini-Leonardou, 1994)

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APPLICATION

The Mintek-NICICO chalcopyrite copper heap bioleachdemonstration plant at the Sarcheshmeh Copper Complex, located inthe province of Kerman, Iran

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APPLICATION

BacTech Mining CorporationToronto, Ontario, CanadaBacTech Mining Corporation Process

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CONCLUSION

1. Bacterial leaching is a revolutionary technique used to extract various metals from their ores.

2. Another methods of extraction such smelting are very energy intensive and require high concentration of elements in ores.

3. 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. Zürich, Switzerland

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