Gold leaching in high copper ore

[johnrughesgold]

Dear,

I am doing tests with a gold ore sample that contains a high content of copper, around 270g/t. I am studying to do a pretreatment with some reagent to block this copper before a cyanide leaching process. Does anyone have a suggestion of what I can do? If I do a direct leach, the copper is all available together with the gold.

What alternatives can I have? POX, BiOX, Autoclave?

 

[Lino1406]

Finely grinding and flotation is the answer - hope you heard about this technology

 

[johnrughesgold]

Finely grinding and flotation is the answer - hope you heard about this technology

We tried to carry out flotation tests before, the problem is that the associated gold is blocked by carbonaceous ores, with high toc. Both tests with direct and reverse flotation obtained negative results.

I now focus on optimization tests on leaching. Perhaps, something that stabilized copper earlier, so that when cyanidation occurred, the process would focus only on gold.

 

[Lino1406]

I assume copper has priority for cyanide over gold (correct me if I'm wrong), hence to reverse it is against nature rules

 

[Deano]

Commercial cyanide leaching of copper ores is carried out using very low cyanide levels, this has the effect of leaching gold preferentially over the copper even though there is some controversy over the mechanism.

You will not get just gold leached, there will be some copper leached which will adsorb onto your carbon and use up a lot of the carbon adsorption capacity.

This copper can be separated from the gold on the carbon by running a cold strip solution through the carbon, the copper desorbs but the gold remains on the carbon until a hot strip solution is used.

You will need to run some tests to see which cyanide level is best for your ore, start at 0.1 grams sodium, potassium or calcium cyanide per litre of water and adjust the cyanide levels up and down to see where it is best for your ore.

You will need to add more alkaline adjusting chemical than usual as the alkalinity usually provided by higher cyanide levels will be absent.Leach times will need investigation, usually these will be so long that a heap leach is the only feasible way to process.

A lot of people have, over the years, tried to leach out the copper before coming in with a cyanide leach, I have not heard of any being successful commercially.


Deano

 

[Rick & Carrie]

Dear,

I am doing tests with a gold ore sample that contains a high content of copper, around 270g/t. I am studying to do a pretreatment with some reagent to block this copper before a cyanide leaching process. Does anyone have a suggestion of what I can do? If I do a direct leach, the copper is all available together with the gold.

What alternatives can I have? POX, BiOX, Autoclave?

A 1 part Sulphuric acid to 5 parts water pre treatment to remove the Copper and most base metals would be a sensible approach to your problem.

As for my choice of leach at this point, T6 at ph2 from GoldmineWorld or Sodium Thiosulphate.

Electrowin the Gold from the leach solution.

The Copper from the pre treatment solution can also be recovered by electrowining after the solution has been concentrated by evaporating away the excess water.

 

[squiggles]

Ammonia - cyanide has been used successfully with problem Cu.
A couple of references to start your research :-
https://www.sciencedirect.com/science/article/abs/pii/S1003632615636421https://core.ac.uk/download/pdf/77021588.pdf

 

[Rick & Carrie]

Ammonia - cyanide has been used successfully with problem Cu.
A couple of references to start your research :-
https://www.sciencedirect.com/science/article/abs/pii/S1003632615636421https://core.ac.uk/download/pdf/77021588.pdf

Way cool find.
Thanks for posting it.

 

[shrewdly]

Although I didn't work in this particular mine, the mine down the road from us had carbonaceous ores. They found that drip feeding a 40% Hydrogen Peroxide solution in their grinding circuit greatly reduced the the carbonaceous component of their ores.