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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Lead Nitrate in Cyanidation (6 replies)

Hauptsturm
8 years ago
Hauptsturm 8 years ago

Do you know if there is any cyanidation plant this using lead nitrate in the process? I am concerned that this increases the lead grade in my Dore. Someone knows how others have eliminated this problem?

(unknown)
8 years ago
(unknown) 8 years ago

If you have some sulphide in solution you can depress it, but if you avoid adding lead nitrate is much better because the lead in the precipitate and will evaporate in the furnace, and also during the smelting lead form a third phase and give a wrong analysis.

(unknown)
8 years ago
(unknown) 8 years ago

How much lead nitrate are you adding? I usually start at around 100 g/t. Other options include pre oxidation, either by adding hydrogen peroxide (an expensive option!) or by using oxygen injection - usually via a high shear type reactor; there are several different styles around. This doesn't however necessarily replace the lead nitrate; it really depends on your mineralogy.

(unknown)
8 years ago
(unknown) 8 years ago

I have worked with lead nitrate on a few projects off and on since late 60's and I have yet to prove that its benefits out-way it detriments. I think it worked better when we were working with relatively clean materials. You need to know your solution chemistry really well if you’re going to use it and most gold mines do not have the lab equipment to monitor the chemistry. It’s difficult because CN solution chemistry is a moving target. The sample you take now doesn't tell you what you need to know if you analyze it two hours from now. We often chase symptoms. If everything in your circuit is constant and you try it, if recovery improves or CN consumption drops you've got a winner.

Hauptsturm
8 years ago
Hauptsturm 8 years ago

Thank you for your support. But different assays were performed (roller bottles) and yielded no results where one can see marked improvement (for our mineralogy), so I decided to continue with the addition of hydrogen peroxide.

Paul Morrow
8 years ago
Paul Morrow 8 years ago

Tried it in one or two operations, it is really a bother. Like suggested above revisit your ore "type" but I agree wholeheartedly with it, oxygen injection by means of shear reactors are a better option. I assume you do add oxygen already but worth a look at the method as my personal opinion is that in sulphide ores you should consider shear reactors opposed to down shaft or spargers in your lead tanks.

Tarun Karakoti
8 years ago
Tarun Karakoti 8 years ago

If sulfide is a problem, pre-floating before cyanidation is the better option.


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