# evaporated Acid/clorox (AuCl)?



## Despotic (Jul 5, 2010)

Silly question I guess.
What would happen if the solution (AuCl) Acid/Clorox were allowed to evaporate?
Either by means of boiling down, distilling or over time.
Where would the gold go?

Don't bash me too hard, I know very little about chemistry. 

-Craig


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## Barren Realms 007 (Jul 5, 2010)

Like a Cheech & Chong movie, Up In Smoke!! 8)


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## Despotic (Jul 5, 2010)

Barren Realms 007 said:


> Like a Cheech & Chong movie, Up In Smoke!! 8)



Seriously? :shock: 
It's hard to imagine gold being evaporated. just floating around huh.
[EDIT] It just feels wrong :lol:


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## Barren Realms 007 (Jul 5, 2010)

Despotic said:


> Barren Realms 007 said:
> 
> 
> > Like a Cheech & Chong movie, Up In Smoke!! 8)
> ...




Evaporate your solution and catch the vapors in a condenser and then test the fluid in the ctach continer and you will have your answer.


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## Despotic (Jul 5, 2010)

No Thanks.
I think I'll just stick with smb. lol
Still a weird thing to me though.
Thanks for the info.


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## Harold_V (Jul 6, 2010)

Despotic said:


> Silly question I guess.
> What would happen if the solution (AuCl) Acid/Clorox were allowed to evaporate?
> Either by means of boiling down, distilling or over time.
> Where would the gold go?
> ...


I suggest you read Hoke for the answer. 

In short, if you evaporate a solution to the proper point, it will start precipitating gold on its own. It will appear much like you see bronze paint, although generally not very concentrated. That, of course, isn't your goal, so you don't want that to happen. 

Hoke talks about carefully adding a few crystals of sodium chlorate to such a solution, to re-dissolve the gold that has precipitated. On the rare occasion I had that experience, I simply added a drop or two of nitric, along with a little HCl. Because I always evaporated with a button of gold present, if I added a drop too much, it was readily consumed by the added gold. 

So you'll understand my madness, my choice was to concentrate my solutions for precipitation. That isn't a requirement for good results. 

Harold


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## Lou (Jul 10, 2010)

Gold (III) acid chloride ("HAuCl4") will, when heated to dryness undergo several oxidation reduction reactions:

HAuCl4 ---> AuCl3 + HCl (off as gas)
AuCl3 <---> AuCl + Cl2 (off as gas)
2AuCl <---> 2Au(0) + Cl2 (off as gas) 

The above is why you may see the glint of elemental gold, should you heat too far.


And this reaction is why you may lose gold, should you heat too far:

AuCl3 (s) <---> Au2Cl6 (as a gas), the equilibrium lies more to the left, but with increasing chlorine atmosphere, it shifts right to the dimer.


Lou


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## butcher (Jul 10, 2010)

If evaporation is just gasses coming off, I would not expect to loose too much metal, I would suspect the gas to be pure in form, the metals in solution I believe would form salts with my acids, 

but as these gases come to the surface and POP they carry liquid, this liquid is dissolve metals, and without a watch glass can be carried out of the pot, even bubbling air into a solution and the minute bubble rising and burtsting can carry liquids, 

if we have a boiling action (not just slow evaporation) much more liquids are carrying away values, at least out of the pot, 

and I feel this is also true that smoke can carry metals, in inceneration, or the gases of chlorides like when strongly heating silver chloride, or some of the PGM, how high our temperature is and how violent our reaction is I feel can play an important role in this, patients is a virtue.


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## Harold_V (Jul 11, 2010)

butcher said:


> and I feel this is also true that smoke can carry metals, in inceneration, or the gases of chlorides like when strongly heating silver chloride, or some of the PGM, how high our temperature is and how violent our reaction is I feel can play an important role in this, patients is a virtue.


I have commented previously, on more than one occasion, that I used to clean out my fume hood about once every second year. It was made to filter, and had an accumulation chamber. The amount of gold recovered after two years of operation ran in the vicinity of eight ounces. That does not include the amount that was trapped in filters, which were changed as required. 

There is no question--values are carried in smoke when incinerating----something that became all to apparent to me very early on in my refining career----thus the special design of my (filtered)fume hood.The losses were most pronounced in incineration of polishing wastes, but a small amount is most likely lost to _any_ incineration. With precautions, they are not losses, as they are recovered by special means. 

Regards losing values to evaporation---Hoke discusses that issue to a viable conclusion. If you evaporate too quickly, you can, and will, lose values. I proved that by turning the side of my travel trailer purple early on, in my learning years. 

_NO ONE _should EVER make reference to evaporation* by discussing boiling*. That sends the wrong message to those that don't have an understanding of proper procedures. One does not boil off nitric--it is slowly evaporated. As butcher so wisely cautioned, if you evaporate too quickly, the tiny bubbles that burst forth carry with them miniscule bits of solution. If you look closely, you can see the discoloration of the vapors, which should appear colorless. If you have a question about evaporating too quickly, simply hold a glass stirring rod in the stream of vapor, condensing some of the discharged vapor. Test the resulting solution with stannous chloride. 

Harold


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## Clneal2003 (Jul 6, 2014)

I had a splash of hcl CL and a little tiny bit of 10k in it on my hot plate. I went to smoke and got side tracked... When I got back all the solution had evap'd and there is some up dissolved metal left smoldered to the bottom of the glass. I'm praying that there is still some gold left. :x


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## necromancer (Jul 6, 2014)

Harold_V said:


> butcher said:
> 
> 
> > and I feel this is also true that smoke can carry metals, in inceneration, or the gases of chlorides like when strongly heating silver chloride, or some of the PGM, how high our temperature is and how violent our reaction is I feel can play an important role in this, patients is a virtue.
> ...




out of curiosity, how much would one need to refine to get 8 ounces in there filter every 2 years. i can only guess (many many pounds)
from what i understand you do not recover from e-scrap.

when i evaporate my solutions i use large coffee filters on top of the vessel.
(method not good for filtering Nox fumes)


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## Geo (Jul 6, 2014)

I believe I remember Harold saying gold was less than $800 an ounce back then. It really isn't much more today counting inflation. point being, cheaper production cost means more product available.


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## Harold_V (Jul 7, 2014)

necromancer said:


> out of curiosity, how much would one need to refine to get 8 ounces in there filter every 2 years. i can only guess (many many pounds)
> from what i understand you do not recover from e-scrap.


To my knowledge, I am the only person to have addressed the issue of attempting to recover lost values in the fume hood--which was used for incineration as well as chemical processing. 

Most folks don't worry about it. I was handsomely rewarded for doing so, however.

I kept no records of the amount of gold I processed annually. Each submission was refined as a unit, with settlement determined by the yield. It is safe to say that I processed hundreds, if not a thousand ounces annually. I really don't know. 

I attribute the majority of the recovered values as having come from incineration of polishing wastes, which I handled in considerable volume. However, any incineration has the potential to cause loss of values, so a filtered fume hood should be a consideration (my fume hood, which I built myself, was constructed of asbestos, so it was fire proof). 

Harold


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