Refining Placer Gold with Black Sands

[The Refiner49er]

Hi All!

Its been awhile since I posted on the GRF.

I am preparing to process placer gold with black sands, and want to do my homework before jumping in.

Has anybody out there run this stuff? I have read about mercury amalgamation, but would prefer to use other methods, avoiding the use of mercury. Hopefully there is an effective way to eliminate the black sands.

Thanks for your input!

John

 

[Oz]

Google "blue bowl". I've heard people talking about getting very fine dust with proper water regulation.

 

[Brandt]

You can use fixer solution or 10 percent citric acid with a bubbler. an the stuff that precipates on top. get it of an process it for the gold. Use AP an a little chlorox and use steel wool to get the gold out.

 

[ChucknC]

Personally I concentrate the placer material as much as possible before I even think about using chemical methods to recover the gold. A popandson sluice works fantasticly well to superconcentrate the gold and other heavies into as small an amount as possible. It will also eliminate all the pesky blonde sands and most of the barren black sands.

The way I look at it, from there you have 3 options. A chemical leach based on what base metals are present, the use of charged Hg, and pyro.
I prefer pyro because you eliminate the other 2 steps entirely.

Remember, the key is to superconcentrate the material as much as is possible. It's like hot smaking meats, low and slow does the trick: low volume of water combined with the slow addition of material. It can take up to 3 runs to get everything.

Chuck

 

[The Refiner49er]

Chuck-

I agree absolutely on concentrating first. Last year I acquired a Hanson 30" centrifugal concentrator without a motor. I installed a PM DC motor from a treadmill, variable speed so it can be dialed in to the type of material being processed.

As refiners, I believe we will undoubtedly see an increase in small prospector activity as gold prices escalate, and am actively promoting to this sector of the market. Placer gold, nuggets, flakes and fines- all of these will need refining to be considered a commodity, and I am determined to develop methodology to process this type of material.

Black sands are notorious for following the gold. I am seeking best methods for dealing with it. I have not processed any as yet, but am thinking of trying the folowing method...
1- Concentration and elimination of all possible contaminates;
2- Pulverizing into a fine granular or coarse powder;
3- Nitric acid to remove base metals and silver;
4- Rinse well and dissolve in AR.

After precip and washouts with HCL, H2O and ammonia, running thru AR again to take the material to fine.

I wonder if HCL/CL would be a viable alternative to AR, perhaps being less reactive to the black sands? Granted, it may be slower, but it would be great to be able to dissolve the gold and leave the BS in the bottom of the beaker.

(BS = Black Sands, I think the abreviation is appropriate) :lol:

Thank you guys for your input...anyone else?

John

 

[The Refiner49er]

One other question-

Aren't most of these sands silica based?

I would think they would be impervious to the acids, separation thereby achieved by gold dissolution and the sands remaining and then filtered out.

Thanks!

John

 

[Anonymous]

One other question-

Aren't most of these sands silica based?

I would think they would be impervious to the acids, separation thereby achieved by gold dissolution and the sands remaining and then filtered out.

Thanks!

John

Unless things have changed since I went to school, yep.
Silica "can" = Sand, but isn't usually the only component.
Silica, (aka: Silicon Dioxide), is most commonly found in nature as sand or quartz. Sand often has other material combined in it, including, but not limited to; salt, corral, fragments of shells and rock, etc.

Getting back to the topic at hand. While I'm not a chemist and my processing and refining experience is minimal, I did find a website and en eBook on Assaying, with lots of information. I haven't heard any "expert" opinions on the websites content, or on the usefulness of the eBook, but maybe someone else here will be willing to comment?

The website is here:
http://www.prospectorsparadise.com/html/basement.html

The eBook is here:
http://www.gutenberg.org/etext/18751

And if you want a ton of prospecting related info including; tools of the trade, assaying, processing and refining, etc, check this out:
http://sleekfreak.ath.cx:81/3wdev/CD3WD/APPRTECH/G10TOE/B1125.HTM
(It can be a busy site, so if it's slow, try again later.)


OGG.