# Fluxes



## Anonymous (Apr 29, 2008)

does anyone have any info on fluxes that I could use to test ore with
just a torch.

I saw an internet site about it but they wanted $450.00 for a system and I think you would be stuck with thier flux mixtures.

I did get a pretty good read on the process on the site but they did not mention chemicals other than litharge and everyone knows that.

thanks

Jim


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## Platdigger (Apr 29, 2008)

James, try Charles Butler, of Butler Labs

http://www.butlerlab.com/


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## markqf1 (May 9, 2008)

James,
Here is a link that might help you.

http://www.nuggethunters.org/poormans-smelting.html.

Mark


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## ChucknC (May 9, 2008)

Mark and guys,
That is a flux for furnaces and it is crappy at best.
Check out the vids on http://www.georgia-gold.com/
The flux simply won't become fluid enough to allow the gold to form a solid prill or bead.

The other problem is the sodium nitrate and soda ash cancel each other out. The NaNO3 Oxidizes the base metals so they can go into the flux while the NaCO3 Reduces the same metals from their oxide to the base metalic state. Does that make any sence to You? The soda ash also attacks any silica in the crucible increasing the chances of a burnout.

What exactly are you trying to do James? Assaying on the fly or what? Give us a little more detail.



Chuck


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## Anonymous (May 9, 2008)

Yes, I am actually hoping to be able to carry a little torch a container of flux and walk around pick up rock or ore crush it up and have a basic idea if further more acruate investigation is worth while.

I know that may be a dream though but I think with all of the time 
people have been mining there should be a couple basic things that you can test on the go with to see if copper, silver, gold are present, not really looking for an assay per se.

Jim


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## Harold_V (May 10, 2008)

ChucknC said:


> The flux simply won't become fluid enough to allow the gold to form a solid prill or bead.



Add some fluorspar and that changes quickly. It's hard on crucibles and furnace lining, but it turns flux water thin, allowing full settling of prills. 

I used a flux of my own design when I ran my waste material and got nearly total extraction, with no prills. My slag was so low in value that it was discarded, not acceptable at a refinery that deals with low grade wastes. 

Harold


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## Platdigger (May 10, 2008)

A flux of your own design.............hmmmmm........care to tell us what it was?
Randy


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## Harold_V (May 10, 2008)

Platdigger said:


> A flux of your own design.............hmmmmm........care to tell us what it was?
> Randy



No problem!

Bear in mind, I incinerated all of my wastes from refining, and stored them as ash. When I was ready to recover values, I had a mixture of incinerated filters, both from solutions and from my hood, along with the values from my stock pot. My waste contained a fair amount of silver chloride, residues from processing jeweler's wastes. 

Because the incinerated materials were easy to lose from the draft of the furnace, I discovered that if I blended the wastes with my flux, added water, then stirred rapidly and poured the mixture to a form of sorts, I ended up with a hard cake that didn't dust. I introduced the cake to my (reverberatory) furnace, after drying well, with no losses. 

The flux consisted of:

(3) parts waste material

(1 1/2) parts silica sand

(3 1/2) parts soda ash

(1/2) part fluorspar

(2) parts borax 

water (enough to make a paste the consistency of pancake batter)

The reaction time was relatively short. You have but a couple minutes before the mix thickens.

Soda ash and fluorspar raise hell with crucible and furnace lining. Were it not for the high value of my waste material, the flux in question may have been too aggressive to be justified. 

Harold


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## goldsilverpro (May 10, 2008)

I didn't realize you were using a reverberatory furnace for this, although it does make sense. I thought you used a crucible furnace. Do you have a photo of the reverb?


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## lazersteve (May 10, 2008)

Harold, 

Looks like it's getting high time for me to tackle the construction of a good furnace. I've been saving my incinerated refining waste for a few years now and I'm itching to try out your flux recipe.

I've still got a ways to go before I can even attempt it, but it's definitely on my radar.

Thanks for the recipe and instructions.

In the past, I seem to remember you mentioning the use of cone molds also, can you expand on that a bit please.


Steve


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## Lou (May 10, 2008)

backyardmetalcasting.com/forum


many knowledgeable people there that will explain how to properly build a furnace. Anyone interested in constructing one right the first time should read this site.


Louis


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## Harold_V (May 10, 2008)

goldsilverpro said:


> I didn't realize you were using a reverberatory furnace for this, although it does make sense. I thought you used a crucible furnace. Do you have a photo of the reverb?



Indeed I do. It's one of my own design, and had electronic ignition. You'll notice it was a tilting furnace, with one of the trunnions acting as the tuyere (air and fuel feed). 

I believe I've posted this picture before. It includes a pair of large cone molds that were used to accept the material after a prolonged soak. The furnace was mounted on casters, so it would be moved to a storage area when it was not in use. Weight was around 600 pounds, as I recall. 

The furnace was about 24" in diameter, with an insulating lining, plus an inner lining of 94% alumina refractory. Because of the aggressiveness of the flux formula, lining life was short lived, so the furnace had to be patched in order to prolong its usefulness. 

Harold


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## Harold_V (May 10, 2008)

lazersteve said:


> In the past, I seem to remember you mentioning the use of cone molds also, can you expand on that a bit please.
> Steve


They're not a luxury, Steve. They're mandatory. Just as assayers use them, so, too, would anyone running a furnace to recover materials that get fluxed. What they do is to stratify the materials in such a way that the values can be easily recovered from flux.

Please note, in the picture I posted, above, that the molds have been well blackened for use. Foundry supplies sell a mold blacking that can be brush applied. I recommend it highly. The material you'll recover from your waste will behave much like gold solder, and will stick to iron molds readily, even when they're somewhat rusty. The flux cover cleanses the surface adequately to permit adhesion. 

While you can pour the charge to an ingot mold, it often quadruples the effort required to free the values from the flux cover because they spread as large as the mold allows, often yielding a thin layer of values, totally covered in flux. It doesn't always chip off easily. 

By sharp contrast, a cone mold provides a minimum surface, which often allows the flux to cleave from the button with one hit of a hammer. Even if it tends to stick, the surface area is much reduced, and you don't risk having a multitude of small pieces of values spread throughout the flux.

Size of your mold would be dictated by the volume of your furnace. In my case, I needed two of them to empty the furnace, with the first one accepting only flux. The second one contained the values and a generous flux cover as well. 

You must become familiar with sulfides, and how to recover values from them. The old trick of inserting some scrap steel (lengths of rebar, for example) while the charge is being reduced plays an important role in recovering all of the values, which are often tied up in the sulfide layer between the button and slag. This is one of the cases where you get full stratification when you melt and pour. The sulfide layer will resemble cast iron in color and texture. None should be discarded without melting with steel. 

Harold


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## markqf1 (May 15, 2008)

Ok,
So where would inquartation play a part in this?

Mark


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## Harold_V (May 16, 2008)

markqf1 said:


> Ok,
> So where would inquartation play a part in this?
> 
> Mark



It wouldn't, not unless the dorè recovered was higher than 25% in gold and platinum. 

Inquartation is used to reduce the gold content of alloyed gold so it can be parted from base metals, a part of the process of refining gold that has silver as a part of its alloy. 

While such alloy can be dissolved in AR directly, it's troublesome, often causing you to recycle portions that refuse to dissolve due to an isolating sheath of silver chloride that forms and becomes impervious to AR. 

(Proper) inquartation avoids the pitfalls of dissolving in AR, and yields a gold chloride solution that is considerably cleaner than one having come from dissolving gold and its base metals. Remember---garbage in----garbage out----the result of mechanical drag-down. 

The furnace in question is used strictly as a recovery procedure. Waste materials, some of which bear silver chloride (an excellent collector of values, by the way), are combined and reduced with the proper fluxes and heat. The end product, or dorè, may or may not require inquartation when refined. In my case, it did not. The silver and base metal content was high enough to allow for total dissolution of the shot (corn flakes) that were poured from the re-melted dorè. Because the source of the waste included spent filters, filters from my fume hood, and collected values from the stock pot, platinum, palladium, silver and gold were recovered. 

Harold


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## calgoldrecyclers (May 16, 2008)

ok. i may be beating a dead horse here, but are you inquiring how to assay possible ores yourself? if im not mistaken, arent assayers using a lead flux? not that it would be considered safe for the hobbyist, but i believe lead is the flux used in asaying. also, if you do happen to find values in your ore through self assaying, you would more than likely need a certified assay report to sell the ore. which, i believe a number of these fellers here would be able to provide to you. 
you could also try the stanous chloride. 
crush the ore, place a knife point amount into a suitable container for acid ( test tube), pour into the receptacle about one teaspoon of concentrated nitric acid, four teaspoons of concentrated hydrochloric acid, heat this solution to boiling, and boil until any gold present has dissolved, to this solution add a pinch of stanous chloride or a pinch of metallic tin filings, the solution will turn purple at the presence of an appreciable amout of gold. 
ferrous sulfate gives a brown precipitate. 

note: if stanous chloride turns to stannic chloride or ferrous sulfate turns to ferric sulfate, it is worthless for this test. these salts are at times unstable, if not stored properly. metallic tin filings are best.


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## Bernie Foley (May 19, 2008)

Hi Harold&members,
Wow what a nice furnace! Now i know you were a retired toolmaker by the looks of that furnace!! Bulletproof cone moulds too!!...Thanks for the picture....worth a thousand words!.......Bernie Foley...


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## Blacktoadd (Jul 26, 2008)

www.lmine.com , Legend Inc has just about everything for mine assay etc. fluxes and crucibles and such. 
Download Standard Methods of Chemical Analysis from google and you will have quite detailed instructions for assay of most metals. 

I have done extensive shopping and should put together a list. I purchased all my life in industry. spent literally millions of dollars. If the fair price is a dollar you will find it for $0.80 and up to $5. You need to find the one who does a big business in that item. They are doing big business in the item cause they are selling it right, and buying in quantity themselves. 
My biggest problem is not finding the item and at a good price its finding someone who has multiple items needed from one dealer. 10 items from 10 dealers is a lot of shipping. 

Bruce


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