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

Hydrometallurgy: Leaching in Heap, Vat, CIL, CIP, Merrill–Crowe, SX Solvent Extraction 2017-04-04T06:57:36+00:00
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Hydrogen Peroxide in CIL Circuit (7 replies)

Kumar Choudhry
1 year ago
Kumar Choudhry 1 year ago

I need to know the best and most efficient way to add hydrogen peroxide into the CIL circuit

Oberstorm
1 year ago
Oberstorm 1 year ago

First off, as hydrogen peroxide is a very strong oxidizer and thus used to destroy cyanide, I doubt if you really want to add it to your CIL circuit. By the same reasoning you probably do not want to add it to any part of your water circuit where it can get back to your leach circuit.

You probably want to add it to your tails just before disposal. Which brings up the point of material compatibility, you need to use special piping usually plastic, stainless or aluminum, but not carbon steel.

Bill Rico
1 year ago
Bill Rico 1 year ago

Are you trying to improve gold leaching or destroy cyanide in the tailings? If it is for leaching then the hydrogen peroxide must be diluted to below 5% or it will consume cyanide. If you want to destroy cyanide then the peroxide still has to be diluted but perhaps down to 10% at most.

The best method to add it is by pumping the strong peroxide into a double nozzle system where it is mixed with water immediately before it goes into the pulp. This avoids the need for a separate tank to hold diluted peroxide.

Kumar Choudhry
1 year ago
Kumar Choudhry 1 year ago

The peroxide is used to improve gold leaching; basically it's used when the normal oxygen injection system failed.

Concerning the injection to the double nozzle system, can you give me the name of a supplier?

Bob Mathias
1 year ago
Bob Mathias 1 year ago

I would recommend my colleagues the review of the Eh-pH diagrams of the systems Au-CN-H2O and other associated systems such as Fe-CN-Au, etc., so the physical chemistry of the leach and recovery system is understood and the plants can be operated efficiently.

Bill Rico
1 year ago
Bill Rico 1 year ago

I'm not sure who supplies the nozzles, but one of the companies that supplies hydrogen peroxide may be able to help. You could try Evonik Degussa Ltd.

http://is.gd/ipKqU3

ibra43043
10 months ago
ibra43043 10 months ago

If I added hydrogen peroxide to cil is that increase the recovery and decrease the time of leaching?

Marshal Meru
10 months ago
Marshal Meru 10 months ago

The effect of hydrogen peroxide on gold leaching rates in alkaline cyanide solution is a matter of controversy and debate. Early studies indicated that the reduction of hydrogen peroxide on gold surfaces is kinetically hindered, and the dissolution rate of gold in oxygen-free solutions containing hydrogen peroxide is very slow.

Other studies have indicated that hydrogen peroxide can play a direct role. One such investigation has demonstrated that for pure gold the leaching rate could be increased significantly using a concentration of 0.015 M H2O2 in a solution containing 0.01 M NaCN at pH 10.

In general, hydrogen peroxide alone is not considered to be a very effective oxidant for use in gold leaching, except under conditions where dissolved oxygen is limited (e.g., at high altitude or in the presence of significant oxygen consumers in the ore). Hydrogen peroxide is very effective for the oxidation of sulfides, although expensive for this purpose. However, it has been used successfully in some cases to accelerate low pressure (atmospheric) oxidation kinetics

Methods of increasing dissolved oxygen levels in leach slurries, for example, by using pure oxygen or hydrogen peroxide as an oxidant, may also need to be considered to maintain adequate gold dissolution rates.

Hydrogen peroxide could also be used for low-pressure oxidation, but the economics are quite unfavorable for most ores, although one notable exception is Pine Creek (Australia), where hydrogen peroxide has been used during gold leaching, principally for sulfide mineral oxidation.

When treating ores that contain oxygen-consuming minerals, pure oxygen or hydrogen peroxide have been added to increase dissolved oxygen concentrations above those attainable with simple air sparging systems.

Review https://www.scribd.com/document/245940186/The-Chemistry-of-Gold-Extraction for the word peroxide

SEE THIS PAPER PDF


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