Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction

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CIL TAILS (2 replies and 3 comments)

J
Kent_725
7 years ago
Kent_725 7 years ago

Is it normal to have a value of  4 to 9 g/tons of Au in CIL Tails? The plant has BIOX process and the ore sample is mineralized as sulfur sulfides-molybdenum. Which part of the process has problem since CIL Tails is considered to have low Au.

M
Mike Rockandel
7 years ago
Mike Rockandel 7 years ago

9 g/t is a lot. What is Au extraction from conc. What is % S oxidation? Maybe you have carbon preg robbing.

J
Kent_725
7 years ago

Extracted Au from conc. is 19g/t and %S oxidation is approximately 75%.

R
Richard S
7 years ago
Richard S 7 years ago

That is not normal to have that amount of gold in a CIL tail.  Since you are presumably using a high activity carbon in the CIL, gold robbing should not be a bit issue and I assume you tested the ore with BIOX and carbon before the plant started operation.  I suspect that a likely cause may be the bacterial population may have been poisoned by something in the slurry.  Oil leaked into the slurry can be a problem and sudden changes in the feed sulfide content could also be a problem.  Usually, BIOX plants keep an innoclum on hand to restart the biooxidation should the population die off.  You can check the slurry for the presence of live bacteria using a microscope which should help determine if the population of bacteria is sufficient or has dead bacteria in it.  Remember also that the oxidation of the sulfides requires sufficient oxygen so you should also monitor the slurry for the amount of oxygen available during the leach.

B
benmuntean
7 years ago

Hi Kent,
That is not normal. Do you have any information regarding kinetic of leaching from lab report. I think the problem is , you have gold/silver capsuled. Try different grading levels.

where do you have lost of gold? Solution or solid?

J
Kent_725
7 years ago

To Richard,
I think all you've mentioned is right specially with the feed sulfides. Feed lately was just 0.3%S and the requirement should >1.8%S. Theres a possibility that bacteria will die or cannot sustain to the process. Thanks for the additional info.


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