Gravity Separation & Concentration Methods

Gravity Separation & Concentration Methods2017-04-04T06:57:23-04:00
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Knelson concentrator feed preparation (4 replies and 2 comments)

Metals Guy
11 months ago
Metals Guy 11 months ago

Hi colleagues, I need ideas on methods of pre-concentration before i feed a knelson concentrator. I operate a 90tph SAG mill, with A KC on the circulating load. My Kc feed, cyclone UF ranges around 5g/t but i would like to upgrade this before i feed the KC. Any ideas of how i can achieve this? Its a gold operation by the way.


Gene Cheeseman
11 months ago
Gene Cheeseman 11 months ago

Could you elaborate on why you want to preconcentrate before the concentrator?  Is your unit currently being overfed?

A pinched sluice may be applicable for this.

Metals Guy
11 months ago

Well, i am trying to get better recoveries from the concentrator.

Gene Cheeseman
11 months ago

As others have stated a scalping screen is essential to efficient CGC operation.

I believe you posted previously that you are using a screen but the apertures were relatively coarse.

2 mm is the industry standard and will minimize coarse gangue competition with fine gold, reduce feed tonnage and reduce downtime.

Unless your concentrator is currently being fed over capacity there likely will not be a benefit to preconcentration of the CUF..

From my experience the two biggest factors in optimizing gravity recovery within a gravity circuit is optimizing cyclone performance (keeps the GRG within the grinding circuit and gives the concentrator multiple chances to recover it) and maximizing feed tonnage (within concentrator limits).

As a centrifuge acts like a pump, increasing the operating speed will also increase throughout (fluidizing water will have to be increased accordingly to counteract increased g-force)

11 months ago
SmartDog 11 months ago

A typical arrangement would first be a screen/trommel to remove obvious oversize followed by a jig, tables, or a sluice.

Jeremy tape
11 months ago
Jeremy tape 11 months ago

See above.  You MUST have a screen prior to your concentrator.  The current work we are doing is to pre-concentrate the feed.  we are taking 5g/t to about 12 g/t.  This results in about 25 g/t to the gravity circuit.  





11 months ago
SmartDog 11 months ago

Jeremy is correct, the best place to do a precon is ahead of the SAG circuit, not afterwards.  this will allow a greater net plant though put and lower the load on the SAG.

That said, without a lot more info it would be difficult to provide any advice that is worth going to the bank with.

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