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How to concentrate the alluvial gold with much magnetic mine ... (4 replies and 2 comments)

Latricia Patton
5 months ago
Latricia Patton 5 months ago

We always come across some customers who want to  concentrate the alluvial gold .

And their alluvial gold is with some magnetic mineral,so some magnetic would stay with after gold centrifugal or jig separator . below is the flow offer by some suppliers.Could you give us some suggestion about the flow :

My doubt: is the jig separator necessary in the flow ? is it better ,if we put the magnetic separator after trommel prior to  centrifugal ? can we separate the magnetic material without magnetic separator ,because we don't need magnetic as concentrate .


flowchart  1.2
5 months ago
minex 5 months ago
2 likes by Bernard Francis and David

Hi Latricia,

You would not put a centrifugal concentrate into a jig.  See attached.  You might put a jig before a centrifugal separator in some instances, to reduce the centrifugal mass feed.  Remember centrifugal separators are batch devices with a high concentration ratio.  They are expensive per unit throughput. 

With alluvial gold it is actually very unusual to find a scenario where gold is so fine, that a centrifugal separator is required.

The reason for putting the magnet AFTER the concentration device is so the mass flow to the magnet will less.  Magnetic separators are usually low volume devices.

Magnets are useful, but also not necessary in most cases as gold can be gravity concentrated from black sands - it's 3 times the density!

Latricia Patton
5 months ago

Hi.thanks for your suggestions. i can not find your attachment.

Jorge Ganoza
5 months ago
Jorge Ganoza 5 months ago
2 likes by Bernard Francis and David

I think a Jig is not necessary in the flowsheet. The separation can involve centrifugal concentrators, spiral concentrators, and shaking tables. Centrifugal concentrators can preconcentrate the material. If you include a spiral concentrator, it is possible to get a better concentrate to feed the shaking table. Other point to keep in mind is the specific gravity of the magnetic minerals, usually they range from 4.5 to 6.5, these values are much lower than the specific gravity of gold, 19.3. The shaking table can be used to clean the concentrate from the spiral concentrator. 

Apparently you work in a lab. You need to include a mineralogical study to determine the presence of native gold, gold bearing minerals, gold particle size, mineralogical associations, particle size distribution, and gold distribution size by size.  

4 months ago

be careful of the density because magnetic particles used to be larger and no discrimination could happen

4 weeks ago
dk 4 weeks ago
2 likes by Bernard Francis and David

The process may be LIMS to remove magnetite followed by WHIMS to recover hematite and ilmenite . For recovery of pyrite , you may use  flotation. There may not be necessaity to go for jigs and instead may use spirals/tables in stages to recover gold. However it is advisable to make a characterisation studies on a sample and undertake beneficiation studies in diffeterent process route to finalise the process. 

1 week ago
polarbear 1 week ago

The post magnetic treatment may be a solution, but the troubles begin when there is no magnetic-gold liberation, This may be analysed following the  Holland Batt criteria utilising perfomance curves and a Mineralogist too!!


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