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

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction 2017-03-23T09:50:58+00:00
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Oxygen consumption in bath CIL tanks (1 reply)

Sandeep Bisht
2 months ago
Sandeep Bisht 2 months ago

Over a week and a half, the dissolved oxygen content of my flotation concentrate carbon-in-leach tank drops by 80% to around 5 ppm. My gold recovery is still OK at almost 90%. This is a batch/Vat setup.


What could explain the oxygen being consumed like this?

2 months ago
Charlie 2 months ago

Hi Sandeep, I saw something similar discussed elsewhere and here is what they say:

Susan (Sue) Ritz This sounds like a mechanical problem to me. Do you inject directly into the tank or do you have a "witches hat" - a cone structure under the agitator the oxygen line is piped into. This cone traps air and allows the injection point to remain free of slurry. The edges of the cone are serrated, giving greater area for dispersion. Your shop can build you one. Next time you drain the tank you can install it and pipe the oxygen into the center of the cone. If it is mechanical, this should fix your problem.

Yves Mazzon You have sulphides that is decomposing and chewing your dissolve oxygen. You can inject clean oil free air into the tanks(don't use compressors use oil free blowers) or add about 50 to 100g/t hydrogen peroxide.

Eugene Dagumi you need to understand what's coming with the concentrate from flotation ( elements composition). Your concentrate might look the same but there might be something building up that end up consuming your oxygen. Possibility of reverse reaction maybe ...

Mark Hargreaves You will need to determine if it is a mechanical problem or a mineralogical problem. Do you have a history of DO measurements over the time-frame in question (ideally 4-6 hourly)? Have you tested the same ore in the lab and found it is problematic? Does DO suddenly drop off (i.e. someone closed a valve or similar), is it a slow time related problem. What is your air flow-rate? does it drop over time, or does the pressure drop? The above should point you in the right direction. I am inclined to think there is a leak somewhere in the low pressure zone, allowing slurry to slowly block the air line, or a problem in air delivery (someone robs air to sand blast and the pressure drops enough to block the line?). Many possibilities and they are usually unique to each site.

List the possible variables and eliminate them one by one.

Tshimangadzo Stanley Masikhwa Good day, I think first and foremost you have to understand your flotation concentrate mineralogy. There might be some base metal sulphides in your concentrate which are taking up oxygen as it is injected into your take. Mineralogy forms an integral part in Extraction metallurgy by suggesting a processing route of the ore. To be able to understand what will happen in the downstream processes, you have to first understand the ore mineralogy.

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