Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal

Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal 2017-03-23T09:42:05+00:00
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Settling Sepiolite clay fines (5 replies and 2 comments)

Bob Mathias
1 year ago
Bob Mathias 1 year ago

How to settle Sepiolite clay fines? I need help settling sepiolite clay fines from saline process water. Anyone out there with experience?

Am trying to clean Mg4Si6O15(OH) 6H2O in a cemented (Duricrust) layer. It does have a fibrous structure at a sub-micron level. Very fine particles -45 micron is liberated during processing.

The clay fines are likely much finer than 45 microns. -45 is the cut-point of our desliming cyclones. I do not think we have ever done a PSD on the slimes. We just want to settle it to clean our process water and send the thickened slimes to the slimes dams. Our "normal" clay fines settle at a reasonable rate and our plant thickeners can handle it, but a certain area of the mine contains sepiolite clay and it doesn't settle at all. We tested a number of flocculants, but without success.

Bill Fraser
1 year ago
Bill Fraser 1 year ago

CSIRO has done much work on clays and solid-liquid separation and thickening.

We also need the acknowledge the fundamental difference between behavior of fine non-clay and clay minerals. Your size of less than 45 microns is very coarse for dispersed clay particles. Clay for paper applications is as fine as 90% less than 2 microns.

As far as settling, it makes a difference if the clay is dispersed. If it is, meaning the particles are not sticking together (coagulated), the water layer on top of a vessel will never be truly free of clay particles. The particles will settle according to size, but some will still be there no matter how long you wait. At the extreme, the finest particles will exhibit Brownian motion, i.e. they will move like water molecules and not settle.

To get all of the clay particles to settle from water, the easiest thing to do is reduce the pH until the particles coagulate. This can be observed in a beaker, where you would increase acid additions until the particles settle with a clear layer on top.

I am not sure what effect the saline component would have on settling but the above would still generally apply.

Victor Bergman
1 year ago
Victor Bergman 1 year ago

Take your sample and start with 100 x magnification, this size particle or groups of particles are in a 35 micron range and become even more smallar thus if you can increase magnificatiin you will see even smaller particle size. Most are precious metals
which are locked into a silica sub particle of the clays , its an art getting these small particles out of the silica base of the clays.

Alan Carter
1 year ago
Alan Carter 1 year ago

If you consider beautification the flow sheet is fairly simple. You can use the fish hook effect and a bank of small diameter cyclones to rip out the fines, thicken them on a vacuum drum filter equipped with a roller or belt discharge then spray dry. It's valuable.

Victor Bergman
1 year ago

Alan, look at the metals interlocked with silica in the clay matrix under a 100 x magnification....And ask yourself how do I get this out?

Victor Bergman
1 year ago
Victor Bergman 1 year ago

A majority of all gold Is located in the clays over the earths surface of which I have 52 procedures that deal with this unseen or not visible range and yes these metallic can be released and placed into solution...they are a mixture of hydroxyl colloidal mixed with natural Nano precious metals and rare earths. I am extracting these mixtures as I speak, its not taught in any college or any mining engineering courses to date. The mining industry is not open minded nor will It ever be.

David
1 year ago
David 1 year ago
David
1 year ago

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