The cost of additive must be taken into consideration.The effect of additive on microorganism needs to be studied before scale up.

The increase of chalcopyrite dissolution by the

presence of some catalytic ions, particularly silver, is

well documented.Treating of ore with silver during acid conditioning to distribute the

silver through the ore before bioleaching is sugested.The recovery of

added silver, by brine treatment of the leach residues to

solubilise silver as a chloro-complex.

The process economics will be improved by recovering silver.

Transformation of jarosite into other iron oxides is needed to enhance the economics.

I would look at the chemistry of hot springs with high mineral content and archea-type, Nitrosomonas, or methanotrope bacteria, Acidic conditions...especially chlorides will ravage the sulfides, oxidizers will as well. Using a red-ox system may give you the effects you want. Finding something tolerant of low pH and dissolved copper may be a challenge.

http://news.nationalgeographic.com/news/2008/11/081105-bacteria-mining.html

Interactions among extracellular polymeric substances (EPS), redox potential and jarosites in EPS space and their effects on bioleaching chalcopyrite

by acidithiobacillus ferrooxidans through the changes of

initial concentrations of Fe(II) and Fe(III) ions have been studied

.

its certain to agree with Sukla sir reply....the ore mineralogy does play a vital role too. Chalcopyrite with high relative distribution of disseminated pyrite grains can help in faster kinetics and less need for additives.

Detailed mineralogy plays vital role in bioleaching of chalcopyrite. During scale up issues so many factors come into play. Exothermic nature of reactions also help in faster kinetics.

Thanks for sharing your ideas Sukla sir, Antonio and Dr.Abhilash.

Contact and non-contact mechanisms have been proposed in the microbial leaching process . The contact mechanism considers that most cells attach to the sulfide mineral surface forming specialized biofilms and that the bioleaching process occurs at the mineral–bacteria interphase The non-contact mechanism involves planktonic bacteria recycling strong oxidants such as ferric ions. Enhancement of Licanantase and other (meta)secreted proteins on the bioleaching rate of chalcopyrite have been reported.

Is it possible to describe the setup of the system. Since I have found that preferred pathways tend to distort the upscaling.

It's known that some additives improve the leaching of the minerals as chalcopyrite, galena, sphalerite etc. Why bacteria or some types or oxidans? The answer in Hydrometallurgy is known and elaborated from scientists (Habashi, ......)

If my additive is showing higher dissolution rates then can I think of upscaling. If I do, then what possibly can obstruct for an application to industry?

Scaling up using additives may be carried out at bench before carrying out the pilot scale.

It is necessary to develop an effective technology to recover copper from chalcopyrite.The heap leaching operation can be impoved by way of increasing temperature,carbon content of heap,adding carbon dioxide,carbonate ores,organic carbon compound and some protein containing materials etc.

In my country there is plant for Leaching and Bio leaching of chalcopyrite - low grade copper ores.

It's very important to solve the problems of these ores - mixed sulphide (65%) and oxide silicate ores (35%).

Conventional Leaching or Micro bacteria leaching?

Investigations have shown second one !!!!!

yeah i do agree sir for the second one. Similar was the case where i had also used the bio-leaching method to recover copper from a mixed sulfide and had optimized the parameters.

Hi I do happy that your experience is same in your conditions.

May be it'll be very interesting to make some joint experiments or study for this technology - Macedonian ores and ores from your region. Joint publishing of papers etc.

Your suggestion is acceptable to us.Mr.Panda can take up the joint R&d work on Macedonian ores and ores from our region.

It's a good idea and possibility for cooperation and scientific work.

Thank you Dr.Boris for the proposal.I would love to work in joint collaboration with you. Yes it will indeed be very interesting to work together. I think we can share more of our future work in direct communication through mail.

My Mail id is [email protected]. I hope you will not mind sending me your email id to me. Thank you, with best regards,Sandeep