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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Gold Leaching in a CIP circuit (7 replies)

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

Can you assist me with information on how I can determine the positioning of the adsorption stage for gold leaching in a CIP circuit set-up. 

As a young metallurgist, I have a lot of questions! I will join a professional society like the South African Institute of Mining and Metallurgy. Memberships such as this usually have a lot of added benefits, such as access to their electronic information and affiliate memberships to sites such as OneMine.

Am also now reading excellent book called “The Extractive Metallurgy of Gold, SAIMM Monograph Series M7”.

Gold Leaching in a CIP circuit is where am stuck now.

Maya Rothman
8 years ago
Maya Rothman 8 years ago

Following classification, clarifier (C1, O'flow to CIC), leach stages, clarification (O'flow to C1 for dilution and/or to CIC), Clarifier U'flow to CIP...refer to OneMine library http://www.smenet.org "Double Thickener Circuit at GoldFields Chimney Creek", Mansanti etal...good for cyanide amenable oxide deposits.

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

Your question does not really make sense, your circuit would normally consist of a series of leach tanks, these will generally equate to a residence time of +/-24hrs, depending on your federate, some places treating sulphide ores opt for a pre-oxidation stage prior to carbon adsorption. The rest of your tanks (with inter-stage screens) will then act as your leach AND adsorption stage(s), with your carbon movement counter-current to the flow of material. This means you will add your fresh/returned (post elution) carbon at the "back" of the leach train and advance the carbon forward usually 6-8 stages (tanks) and then recover for elution. Thus the flow sheet in a nutshell.

Victor Bergman
8 years ago
Victor Bergman 8 years ago

CIP means Carbon IN Pulp, and the adsorption is in the leach tanks. A CIL ( Carbon in Liquor) circuit would have the adsorption after the leach tanks (or pad). And then it would depend on if (in tank leaching) you are running counter current current (add fresh liquor to last stage and take pregnant liquor off first stage) (generally most used) or con-current. If you are using heap leaching it is after the liquor drains from the pile.

Bob Mathias
8 years ago
Bob Mathias 8 years ago

To determine what is happening during leaching and adsorption, I would suggest that you conduct profile sampling over the leach train, i.e. take samples from each leach tank and split out the Solids, Liquids and Carbon components, so that they can be subjected to an assay. Then I would suggest you look up and use the rate equation usually used to design Carbon-in-pulp plants (“kn” model).

JohnnyD
8 years ago
JohnnyD 8 years ago

In a CIP circuit the leach tanks are separated from the adsorption tanks. I have been to a mine which used 4 leach tanks and 7 adsorption tanks. The leach tanks were taller and wider than the adsorption tanks and they come before the adsorption tanks.

The leach tanks being taller than the adsorption tanks allows flow by gravity from the last leach tank to the first adsorption tank.

Bob Mathias
8 years ago
Bob Mathias 8 years ago

If to understand residence time as time required to (a) reach max gold loading on the carbon and (b) provide min gold concentration in the tail, one need to run absorption kinetics study. Gold feed solution must have composition of liquid phase of the leached pulp. Use large carbon to solution ratio to simulate constant gold concentration. Analyze gold in carbon samples in definite periods of time. I would suggest to reach total time 48 hours at least. Thus you will find residence time for you solution. It doesn't matter if you exploit CIP circuit. Though it is possible to use pulp instead of clean solution in this study.

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

A brief comment on CIP circuits: At GoldFields Operating Co (Chimney Creek, Nevada, early 90's), the cyanide amenable oxide ore (sans pregnant robbers or cyanicides) was ground to a P80 74-micron & leaching begun in the ball mills; cyclone O'flow (~60% Au leached) was introduced into a conventional thickener & the overflow (TOF-1) was partially diverted to a CIC circuit; thickener U'flow was pumped to a 3-tank agitated leach circuit with a second thickener receiving the diluted (TOF-1) slurry (addnl 25-30% Au leached); TOF-2 was pumped to a CIC circuit & the U'Flow was transferred to CIP (~5-10% Au leached)...so essentially CIP was used as a scavenger circuit...hope this concept assists w/your assessment.


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