thanks very much for your reply.

but I am taking about production scale 600 ton/hr not lab scale.

Hello Mostafa!

I have an experience with clay processing - dispersing, deagglomeration and slurry preparation e.t.c. As I understood we are talking about pure gold (Au), we have some unique equipment for in-flow dispersing and deagglomeration, After that obtained suspension with Au particles you need centrifugate, or use other method for gravitational particle separation. 600 ton/hr it is huge amount, but this technology can be scalable. For more details please use powder.al.b[at]gmail.com

Hello dear Mostafa;

I have some solution for you?!

1) please check PSD of clay in the slurry and check presence of gold in fine particle size ranges (in order to avoid  gold loss prior floatation); in this case you can use hydro-cyclone clusters for clay (particles normally finer than 0.02mm) removal prior flotation; it is normal good way; in overflow stream you have clays and you can feed cyclone underflow stream to flotation cells. If you need accurate hydro-cyclone system for fine particles removal like clay; I am collaborating with well-known brand for supply of hydro-cyclone with very fine cut-size.

2) if you can not use hydro-cyclone for clay removal; you should use good depressing and dispersing agent such as Sodium Silicate in order to avoid entrainment of Kaolin during frothing.

Please don't hesitate to contact me in case of any further questions;

Regards,

Hamed

thanks Dr Andrei

Dr Hamed I think depressant will be good for my issue as our gold is trapped in sulphide mineral with in 9 um, thank very much for you help.  

Dear Mr. Sabry,

use KOH, it is a very cheap and easy to handle chemical compound which dissolves kaolinite. Prior to that you should take a closer look at the kaolinite Si/Al ordering that may have an effect on the decomposition rate and speed of this 7 Å- phyllosilicate.

Best regards

Harald G. Dill

Dear Mr. Sabry,

According to the fact that you need finely milled material for flotation I'm thinking about a very simple and environment friendly method of removing majority of the clay fraction. Did you try to simply make a water suspension in a basin and to remove suspended clay after certain time to allow heavier fraction to settle-down before leading it to flotation?

Best regards

Mirka

Dear Mostafa Sabri,

Particular for the depression of clay minerals in gold flotation, bio polymers can be used. On the web page of  find pionera you'll find a few somehow helpful diagrams:

http://pionera.com/Applications/Flotation-depressants/Depressants-for-Clay

Bad recovery also can have other reasons. Which collector do you commonly use? Which max. particle size do you have? Which cell type?

kind regards

Dr. Rüdiger B. Richter

Sorry Mostafa,

just have seen, that you speak about 9 microns in a sulfide mineral (obviously pyrite).

In case you need to grind the ore down in this range the reason for bad recovery maybe not only the clay alone.

Glueck Auf!

Ruediger

The method depends on quantity of clay in your ore and mode of it's occurrence.

First of all you may try attrition scrubbing the ore prior to milling, washing it in a perforated drum to remove clay from coarse crushed material. it will give you improvement in milling and flotation and increase flotation feed rate.

You may also use long cone cycloning on ground product if you have no gold/pyrite in fines. It will take most of the slimes out of the circuit.

To depress the clays in flotation you may try sodium silicate, sodium polyacrylate, starch, dextrin or other cellulose compounds using them before addition of collector and frother. NaSiO3 is probably the cheapest.

You can send us some samples to give you the most concrete solution.

The method depends on quantity of clay in your ore and mode of it's occurrence.

First of all you may try attrition scrubbing the ore prior to milling, washing it in a perforated drum to remove clay from coarse crushed material. it will give you improvement in milling and flotation and increase flotation feed rate.

You may also use long cone cycloning on ground product if you have no gold/pyrite in fines. It will take most of the slimes out of the circuit.

To depress the clays in flotation you may try sodium silicate, sodium polyacrylate, starch, dextrin or other cellulose compounds using them before addition of collector and frother. NaSiO3 is probably the cheapest.

You can send us some samples to give you the most concrete solution.

Dear Ilja (Privietik!)

I have understood, that they don't do all the things you rightly have recommended! The clay is just in the pulp and for that they may need an immediate and cheap solution.

If it is already in pulp, the chemicals as I mentioned can be utilized. If the clay represents a large percentage on ore it may not help at all. Reducing the pulp density will be of a benefit.

I would suggest doing brief mineralogical study of ore to find out the variability of its composition. Mapping to delineate the clay rich zones would be also beneficial to treat this ore differently.

Dear Mostafa,

We as BAUER also have our own bio polymers available in our large group. If you have a real problem with your clay and you'll find a solution, for that you can contact me under [email protected]. My Competence Center is performing flotation lab-scale tests on a regular base and therefore we have plenty of practical experience and a certain practice to perform such things professional.

Maa'salama

Ruediger Richter, Abu Dhabi