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Aborigenic Strains of Gold Ore Deposits

#KR-1934


Microflora Aborigenic Strains of Kyrgyzstan Gold Ore Deposits for Using in Biogeotechnology

Tech Area / Field

  • BIO-MIB/Microbiology/Biotechnology
  • BIO-IND/Industrial Biotechnology/Biotechnology
  • CHE-ANL/Analytical Chemistry/Chemistry
  • ENV-EHS/Environmental Health and Safety/Environment

Status
3 Approved without Funding

Registration date
15.03.2011

Leading Institute
National Academy of Sciences of Kyrgyzstan / Institute of Chemistry and Chemical Technology, Kyrgyzstan, Bishkek

Collaborators

  • University of Turku / Finnish-Russian Joint Biotechnology Laboratory, Finland, Turku\nMichigan Technological University, USA, MI, Houghton\nLaurentian University, Canada, ON, Sudbury

Project summary

The purpose of the work - the searching and selection of microflora strains from natural objects of gold ore deposits of Kyrgyztan, and also producing of technogenic strains (on the basis of microbe banks) perspective for their further use in biogeotechnology.

The resources of Kyrgyztan gold reserves are estimated by different authors to be 2.5-3 thousand tons.

The current Kyrgyztan technologies allow to extract only 70-80% of the gold in the ore. The rest goes to the waste.

Two main problems of gold extraction exist:

  • when gold is in crystal lattice of sulphide minerals (hard ores);
  • when gold is in solution, but is not extracted by ordinary flotation methods as its particles have microscopic (0.1-100 mcm) or submicroscopic (0.0001-0.1 mkm) dimensions (finely dispersed).

For solving of the first problem of the bioleaching of metals from hard ores is accomplished with microbes like Acidithiobacillus ferrooxidans. For solving of the second problem can be based on biosorption of dispersed gold by cells of living microorganisms.

The first and main stage of any biotechnology, on which it’s effectiveness depends, is isolation of highly productive microflora strains, able to carry out put for concrete technology tasks, may be metals oxidation or reduction, metals biosorption or sedimentation etc. The important task is also purification of industrial sewages from heavy metals and various toxic substances (for example, of cyanides). Last time row of new approaches was marked in solving of these tasks with using of microorganisms.

At present a new technological line – biogeotechnology has been adapted for a wide use for metal extraction from ores, concentrates, mountaineous minerals and solutions under the action of microorganisms and their metabolites. A whole series of successfully applied technologies for sorption of noble metals is known.

However, there are problems of application of those biotechnologies varying from deposit to deposit. It has been shown that it is necessary for each deposit to select its own microflora (know-how), because components of industrial solutions may render inhibiting effect on non-adapted microflora. More effective processes can be based on isolating aborigenic microbial strains from natural deposits followed by their propagation and later use.

It is proposed here to produce aborigenic microflora strains for extraction of gold as follows:

  • Bioleaching of gold and accompanying metals from sulphide minerals (biooxidation);
  • Metal biosorption;
  • Destruction of cyanides and their complexes in industrial waters of Gold Extraction Factories (GEF) with liberation of gold from KAu(CN)2 or NaAu(CN)2.complex.

Preliminary laboratory tests had shown rather hopeful results, gold bioleaching on 99,5%.

This development is very timely an economical for applications to gold extraction from ores and industrial waste of Kyrgyz Republic.

In the case of Project successful completion new complex biotechnologies for gold-ore deposits allowing to increase gold extraction on 15-20% without additional deposits exploitation will be offered.

It is important to notice that these methods are environment and energy friendly and that at present biogeotechnology is not used in Kyrgyztan. One of the main reasons is the absence of technogenic strains of microflora, adapted to composition of the ore of each concrete deposit. The creation of collection of aborigenic strains isolated from different natural deposits of Kyrgyztan and tested on possibility of their using in hydrometallurgy, will help to solve very significant energetic, environmental and economically important problems.

Project tasks:

  1. Ensure ecological purity of Kyrgyztan natural medium in expense of cyanide decontamination in industrial GEF waters.
  2. Develop technology of increasing gold manufacture in expense of cutting down its loss in waste.
  3. Create the bank of technogenic microorganisms perspective for biohydrometallurgy.

Executors of the Project will be weapon specialists and research workers of National Academy of Sciences of Kyrgyz Republic.


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