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Intensive Leaching Parameters (2 replies)

Tarun Karakoti
9 months ago
Tarun Karakoti 9 months ago

For some time now, dissolved oxygen levels, cyanide concentration and pH at our ILR Plant keeps decreasing as leaching advances with a very high increase in temperature (around 89 degrees Celsius) and the evolution of a gas which i suspect to be ammonia?

Kumar Choudhry
9 months ago
Kumar Choudhry 9 months ago

This phenomenon indicates the occurrence of some exothermic oxidation Rx which consumes oxygen and generates acid. It normally happens for ILR plant treating mixed ore or sulphides concentrate. Does your ore/concentrate contain a bit of sulphides? The pungent smell might also come from H2S or from the oxidation of other salts and sulphide species.

You may have to control a bit down your DO level and adjust your CN/DO ratio correctly to reduce the oxidation degree in your ILR.

9 months ago
Unterstarm 9 months ago

I agree with the assessment he is making with the relative small amount of data that was available. The oxidation of the sulphides may even be beneficial to Frank's intensive cyanide leach circuit as the oxidation process may be liberating more of the fine gold. However, you will need to have more free cyanide available to extract this gold. You can also include an oxidation step into your intensive leach cycle - this may reduce your cyanide consumption.

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