# High density liquid



## kjavanb123 (Apr 17, 2009)

I have heard some labs use this "special liquid" to remove the unwanted soils from gold-bearing placers. Any ideas what is that liquid that is heavier than let's say soil with silica and other stuff, yet ligher than placer gold which will sink in this liquid, while all the other stuff are on top?

Thanks


----------



## Lou (Apr 17, 2009)

There are numerous super dense solutions.

The most popular is sodium polytungstate.


Time was when thallium malonate was used...but the thallium part is extremely toxic.


Specific gravity separation is the first and usually the easiest method employed.


----------



## goldsilverpro (Apr 17, 2009)

Isn't there also some way to achieve high "effective" specific gravities with some sort of slurry? I seem to remember reading something about that.


----------



## Anonymous (Apr 17, 2009)

ferro silicon super fine but its expensive.


----------



## kjavanb123 (Apr 18, 2009)

I just talked to a lab analysis, the liquid with density of 3.5 is called BEROMOFORM or something like that. available to you in any chemical store.

All minerals with density lower than 3.5 will stay on top and the heavy ones get dropped at the buttom. This is another piece of puzzle i was looking for in my gold ore processing


----------



## kjavanb123 (Apr 18, 2009)

Then again when asked for the price per litre of BORO-MOO-FORM is around $300. which in my case with 20grams per ton Au, and 50 grams of Ag in my grind ore, seems like a costly thing.

Another solution there is an acid that dissolve Sio2 in it, forgot the name, but that is only acid that is kept in plastic containers 

peace


----------



## Lou (Apr 18, 2009)

You're talking about bromoform. That works, but it's specific gravity is less than 3.5 (actually 2.9 g/mL).

Make sure to use it in the hood, it's a hepatoxin (attacks liver) and a narcotic if inhaled.


The acid that works is hydrofluoric acid, or a salt that produces it in situ. Also, phosphoric acid will dissolve silica in some circumstances.


Bromoform should be not so expensive in larger quantities, but it is an environmental hazard and is being phased out. Recall that a liter is 2889g of bromoform!


----------



## ck (Apr 18, 2009)

deleted


----------



## Oz (Apr 18, 2009)

Nothing like being a paid chemist and just ordering what you need.


----------



## nicknitro (Apr 18, 2009)

This is a liquid at room temperature KJ? 

It kinda sounds like the Ebay Refining method mentioned a few times on this site, which is reportedly Bismuth. However bismuth must be heated, to liquify, then the gold is absorbed by the Bismuth while all the lesser metals float on top. Seems kinda similar.

Same "Stuff"??
Nick


----------



## kjavanb123 (Apr 18, 2009)

nicknitro said:


> This is a liquid at room temperature KJ?
> 
> It kinda sounds like the Ebay Refining method mentioned a few times on this site, which is reportedly Bismuth. However bismuth must be heated, to liquify, then the gold is absorbed by the Bismuth while all the lesser metals float on top. Seems kinda similar.
> 
> ...




interesting, but i am using this liquid to remove unwanted soil, and process the gold-bearing minerals that are left at the bottom, Bismuth to me sounds works for placer gold ( free from minerals ). Plz advise.


----------



## ck (Apr 18, 2009)

deleted


----------



## kjavanb123 (Apr 18, 2009)

ck said:


> have a look at this: http://www.google.ca/patents?id=rNYkAAAAEBAJ&pg=PA2&lpg=PA2&dq=US+Patent+5692620&source=bl&ots=Aiy9ZEx3Cp&sig=7jagiQodmEzleMY24dqtgA2badY&hl=en&ei=CKjpSdeRBI62tAPZnY3qAQ&sa=X&oi=book_result&ct=result&resnum=8#PPA1,M1
> 
> seems to be very simple to build.



That was interesting. Yet that is used for gold placer ( i.e. streams in Ca or Alaska)

My ore contains gold as part of minerals. So I am going to use this method to recover gold and silver.


----------



## lazersteve (Apr 18, 2009)

I would look into soda ash and lye at elevated temperature for dissolving silica if that is your goal.

Steve


----------



## Irons (Apr 18, 2009)

lazersteve said:


> I would look into soda ash and lye at elevated temperature for dissolving silica if that is your goal.
> 
> Steve



One thing to watch out for is residual soluble silicates. Add HCl and it forms a gel that is very difficult to get rid of.

A final boil in clean NaOH with lots of rinsing works.

Miss a step, make a mess.


----------



## Lou (Apr 18, 2009)

What Irons and Steve said is a good option, and is the one I most frequently turn to but it slipped my mind. Unfortunately, boiling caustic solutions are very hard on glassware (but not on some polymers).


Now that I know what he is trying to do, I would abandon any method that involves dissolving away the impurities. The general rule is: if there is a trace of value in a matrix of impurities, you selectively remove the traces; if there is much value and a trace impurities, you selectively remove the impurities. Makes sense eh? 

You'll never have economic success if you try to chemically remove bulk material just to obtain a small amount of gold. You remove the gold from the gangue, not the gangue from the gold!!


----------

