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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Reduce material' settling in gold leach tanks (12 replies)

Helena Russell
2 years ago
Helena Russell 2 years ago

I would like to know if anyone has ideas on how to reduce settling of materials in leaching tanks in Gold production. The ore treated are oxide and fresh rock.

Victor Bergman
2 years ago
Victor Bergman 2 years ago

Particle settling is dependent on size, shape and density of the particles and the upward velocity of the water. If you are having an issue you should check your circuit and approximate the factors. Perhaps a move to a slightly finer final grind at the cyclone underflow.

Check your pulp density, it should be within the range of 38%-42% solid feed from the grinding circuit cyclone overflow, and also proper aeration should b observed. Also check your mixer design and tip speed as well as tank configuration to produce good slurry mixing and avoid " dead spots" and sanding.

Replace your agitators when they wear out? Monitor power draw VS speed to have an indication of when to take physical measurements. More details what you are treating and also what agitator you are using and we can see if that is where the issue lies? Monitor particle size distribution PSD of leach feed.

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

As long as the solids are high enough and there is no detriment to downstream properties you could add a very small amount of pure mineral suspension aid that would eliminate settling even after long periods without agitation. This material is also a grinding aid and can increase throughput in wet ball mills, which is a good addition point. Let me know if you would like some details.
Make sure your sizing is working properly then increase pulp density. Other than that you are going to have to redesign your agitators.

What is the PSD of the leach feed?
Dimensions of the leach tanks?
Do you have viscosity data on the slurry?

Monitor the solids density and feed density of the slurry. Do you have the correct agitator(s) installed in your leach tanks?

Bill Rico
2 years ago
Bill Rico 2 years ago

Maybe you should look at your densities and your grind as well. Depends also on your ore competency.

John Koenig
2 years ago
John Koenig 2 years ago

Particle settling is dependent on size, shape and density of the particles and the upward velocity of the water. If you are having an issue you should check your circuit and approximate the factors. For some help look at: SDM Pulp Calculations found here: ttp://http://www.smartdogmining.com/software/default.html can be used as a rough check of the behavior.

For some background information look at An Introduction to Gravity Concentrators & an Introduction to Flowing Film Concentrators found here: http://www.smartdogmining.com/notebook/default.html

Helena Russell
2 years ago
Helena Russell 2 years ago

The particle sizes cannot be altered since the mill in use was built for oxide ore but we have gotten to the point of treating fresh rocks. I therefore want to know if there are mechanical ways of reducing the settling rate of the material. Again, we have tried the use of viscosity modifier to increase the flow downstream but it was of no positive results.

Ace Levy
2 years ago
Ace Levy 2 years ago

The next solution is to increase the solution velocity in your tanks by either bigger agitators or different impeller designs. It still is a function of shape, size, density and water velocity. Viscosity does enter into it, but it only helps. Lowering the viscosity will increase the settling.

Bill Fraser
2 years ago
Bill Fraser 2 years ago

Several Gold sites globally we service have the same issue and most have just reverted to a simple bottom plate air injection system. Don’t try to reinvent the wheel.

Dizzy Flores
2 years ago
Dizzy Flores 2 years ago

What is mesh of grind? What is the pulp density in the agitator tank? Check your aeration should be 8 to 10 mg/lit dissolve oxygen.

Bob Mathias
2 years ago
Bob Mathias 2 years ago

To reduce the amount of precipitated material, it is necessary to apply the stirring operation except aeration (sparging). In this case, the material of the so-called "dead" zones will rise in the range of the impeller. In the case of processing gold ore, it will improve including the leaching of gold (cyanidation).

Jean Rasczak
2 years ago
Jean Rasczak 2 years ago

I am not a professional type of person for this, but because of I have been in mining industry for over 20 years and have processed different type of ore such as: Fe,Cu,Pb,Zn include Manganese. So i just have lots of seeing things that happened in the mine site. Here what i have seen is that while the ore still on conveyor belt before reaching crusher to stockpile, there is a MAGNET that can pick up the unwanted materials from the belt and push by hydraulic ram to the side and release as the waste. The only go to crusher to stockpile are the clean ore.

David Kano
2 years ago
David Kano 2 years ago

Probably; the slurry flow speed is less than the settling speed, or the slurry settling rate. If is not possible increase the slurry speed (RPM) to keep the solids in movement into the tank; could install a recirculation pump, to recirculating the slurry in the bottom of tank, The same way used in the Vertimills.

Sugar Watkins
2 years ago
Sugar Watkins 2 years ago

We run the Tiammo Machine for chloride/fluoride determination on oxide ore and as well as Eltra-800 machine for carbon/sulphide determination on Cu ore.


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