# REDUCTION OF GOLD



## goldmet (Aug 7, 2016)

Hello friends. I want to share something with you intertesante.(interesting)
If an alloy of gold with aqua regia dissolves and filtered. The liquid containing the gold is slowly brought to dryness in a ventilated area to prevent acid vapors.
When dry the temperature is increased and something fantastic happens: reduced gold and other metal salts are in the form of chlorides.
To purify gold, wash with hydrochloric acid, as often as necessary and then with distilled water.
When this pure gold may be agglomerated with a glass rod and rubbing takes carefully bright yellow color.
I hope to discuss this ....


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## goldmet (Aug 7, 2016)

Final gold with 99.9% or more purity if chorhidrico (Hydrochloric)well rinsed with distilled water and acid.


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## Topher_osAUrus (Aug 7, 2016)

Scientists have been crystalizing to purify for ever. I believe it isn't done this way when refining gold because of the losses than can occur when calcining or removing the chloride ions from the gold chloride to reduce it.


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## butcher (Aug 7, 2016)

If I understand you are not really driving off all of the chlorides, not raising the temperature High enough to dry out the chlorides salts.
I can see where you could get rid of most of the base metals like copper before making the fairly pure gold chloride solution, and most of the lead or silver from the process removed before, and during filtering. With easily drying, you can wash out most left over impurities, with good washing techniques to come up with the product you stated.

I find this interesting and can see where it could work as stated if done properly. My question to myself is why would I try this unless as an experiment, I could chance a loss of some of my gold if done wrong, through volatilization, and if I had my gold ready for the process using a reducing agent at that point is not much trouble to finish up.

goldmet, Thanks for sharing I do find this interesting.


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## goldmet (Aug 8, 2016)

butcher said:


> If I understand you are not really driving off all of the chlorides, not raising the temperature High enough to dry out the chlorides salts.
> I can see where you could get rid of most of the base metals like copper before making the fairly pure gold chloride solution, and most of the lead or silver from the process removed before, and during filtering. With easily drying, you can wash out most left over impurities, with good washing techniques to come up with the product you stated.
> 
> I find this interesting and can see where it could work as stated if done properly. My question to myself is why would I try this unless as an experiment, I could chance a loss of some of my gold if done wrong, through volatilization, and if I had my gold ready for the process using a reducing agent at that point is not much trouble to finish up.
> ...


In losses are small amount minimas(minimal losses). To avoid losses, gasses can be collected by condendador (condenser)coupled to a flask.


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## 4metals (Aug 8, 2016)

Please detail your rinsing process to dissolve the base metal chlorides.

Do you have any photographs of the rinsate with the base metals in solution? Has this solution been tested to assure all of the gold remained insoluble?


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## anachronism (Aug 8, 2016)

I've done this myself albeit by accident.

An AR boilover onto a ceramic hotplate leaves gold powder on the surface, so I can see the theory.


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## goldmet (Aug 8, 2016)

anachronism said:


> I've done this myself albeit by accident.
> 
> An AR boilover onto a ceramic hotplate leaves gold powder on the surface, so I can see the theory.


I have seen painting ceramics with this method.


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## Topher_osAUrus (Aug 8, 2016)

goldmet said:


> anachronism said:
> 
> 
> > I've done this myself albeit by accident.
> ...



That is interesting.

How well does the "paint" hold up when done like that?
Does the gold adhere to the porous structure of the ceramic well?
Or is it applied before it goes to the kiln and gets baked on further?


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## Lou (Aug 8, 2016)

I don't see the need to do this, or the benefit.

Governing reactions of what you are doing:
HAuCl4 --> AuCl3 + HCl
2 AuCl3 <--> Au2Cl6
Au2Cl6 <--> 2AuCl + 2Cl2
2 AuCl --> 2 Au + Cl2

Gold is gas phase volatile as its (III) chloride dimer. I do this when growing gold crystals via gas phase chemical transport. Over many months, large (1-3+ cm) crystals of very high purity gold will grow at the disproportionation end of the tube. 


One can likely evaporate with sulfuric acid until dense fumes begin--the first fumes come off are just HCl. The end result ought to be cleaner metallic gold and easier rinse out of the CuSO4 and ESPECIALLY the Ag2SO4 when compared to heated and dried AgCl, which you will never rinse out of your gold (not with ammonia, not with HCl...not after that heat history). Ag2SO4 is very soluble in sulfuric acid solutions of high concentration; copper sulfate less so (more so in water). 

There is no volatilization of gold in that fashion and all the chlorospecies (AgCl, CuCl2, FeCl2, ZnCl2) are quantitatively transformed into their respective sulfates. Sulfate anion is much more stable than Cl- but one of the products of any gold sulfate salt formed will probably be SO2 and water, both volatile, both preventing the gold from going any where. 

Topher, such solutions are made up in organics. It's usually done w/ AuCl3 dissolved in a nice smelling solvent of some sort (often piney smelling, at least with the Degaussa stuff I used to process by the gallon). You can paint onto glass or ceramic, fire it in a kiln, and have a gold or platinum residue that is either metallic or needs some burnishing. 

Lou


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## Topher_osAUrus (Aug 8, 2016)

Lou said:


> I don't see the need to do this, or the benefit.
> 
> Governing reactions of what you are doing:
> HAuCl4 --> AuCl3 + HCl
> ...



Excellent, informative post Lou, thank you.

Gave answers and insight into questions i have had, and ones that I haven't even conjured up yet.

Hope the baby girl isn't giving you too much grief. 

-topher


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## upcyclist (Aug 12, 2016)

Lou said:


> Gold is gas phase volatile as its (III) chloride dimer. I do this when growing gold crystals via gas phase chemical transport. Over many months, large (1-3+ cm) crystals of very high purity gold will grow at the disproportionation end of the tube.


Wow, that sounds very cool. Pics or it didn't happen


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## Topher_osAUrus (Aug 22, 2016)

upcyclist said:


> Lou said:
> 
> 
> > Gold is gas phase volatile as its (III) chloride dimer. I do this when growing gold crystals via gas phase chemical transport. Over many months, large (1-3+ cm) crystals of very high purity gold will grow at the disproportionation end of the tube.
> ...



http://www.livescience.com/44717-worlds-largest-gold-crystal.html




Pretty neat stuff, although I am not sure if it is comparable to what lou makes.


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## g_axelsson (Aug 23, 2016)

Nice crystal, but that's a natural occurring gold crystal if my memory doesn't fail me.

This is a synthetic gold crystal made by gas transport.
https://en.wikipedia.org/wiki/File:Gold-crystals.jpg

Göran


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## Lou (Aug 23, 2016)

Either Ivan made that one or myself, Goran. Not sure.


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## Topher_osAUrus (Aug 23, 2016)

Now THAT is beautiful..


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## goldmet (Dec 16, 2016)

Topher_osAUrus said:


> Now THAT is beautiful..


Thanks for appreciating the post


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## goldmet (Dec 16, 2016)

Very interesting the subject but when it dissolves 1 gr of pure gold with regal water and reduces with heat, the loss is undetectable. I have verified it.
However, when using a gas condenser, no gold is detected.


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## eaglewings35 (Jan 27, 2017)

butcher said:


> If I understand you are not really driving off all of the chlorides, not raising the temperature High enough to dry out the chlorides salts.
> I can see where you could get rid of most of the base metals like copper before making the fairly pure gold chloride solution, and most of the lead or silver from the process removed before, and during filtering. With easily drying, you can wash out most left over impurities, with good washing techniques to come up with the product you stated.
> 
> I find this interesting and can see where it could work as stated if done properly. My question to myself is why would I try this unless as an experiment, I could chance a loss of some of my gold if done wrong, through volatilization, and if I had my gold ready for the process using a reducing agent at that point is not much trouble to finish up.
> ...


Okay, I know this is an old post, buy what a doozy!!! Help me understand this.... I can take some gold solution that has been thoroughly filtered, add a goodly amount of distilled water, then I can over low heat, evaporate it down, and it will turn back into a gold powder?
You don't have to use SMB to drop it? Does this summarize what the OP is saying?


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## Lou (Jan 27, 2017)

No need to add water. You just boil off a bunch of acid.


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## eaglewings35 (Jan 28, 2017)

Lou said:


> No need to add water. You just boil off a bunch of acid.


So, by simply boiling off the acid, the gold will precipitate out?
Thats amazing !!!
At what point will the acid crystalize? Should I just do barely a rolling boil?
I plan on putting some coffee filters on top of my jar, secured by a rubberband.
Hopefully this will catch any values that may be lost due to boiling, and I can test the filters later for gold.

Still, I ask, if there are any other metals, like silver, platinum, ect. that are dissolved in the solution too, how will the boiling off the acid affect them? Will you be able to see them?
Can they be separated out at that point, or will they be bonded still with the gold?

Thanks


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## Topher_osAUrus (Jan 28, 2017)

Dont boil!
Evaporate slowly.

Any silver in solution would be a pain, as its in chloride form and evaporating the moisture would dry it out. And as Lou pointed out earlier in the thread, dry silver chloride doesn't have very many options to put it in solution, or get it back to metallic form.

This would probably be best if done with a relatively pure gold solution..

Harold spoke of, many times, when he evaporated his gold solutions down metallic gold would begin to precipitate.

I think I'll stick to standard precipitation methods.. Using sodium metabisulfite is about as easy as it gets.


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## aga (Jan 28, 2017)

eaglewings35 said:


> At what point will the acid crystalize? Should I just do barely a rolling boil?


The AR acids won't ever crystallise by heating, they'll volatilise and drift out of the pot into the air.



Topher_osAUrus said:


> Dont boil! Evaporate slowly.


Lou clearly knows his stuff and probably uses 'boil' as a shorthand way to say 'evaporate at an appropriate temperature' ( = a lot less typing !)

One of the problems with simple boiling is the splashing, which throws some of your gold-containing liquid away.

Another problem is how fast the acid vapours are being made - you need to make sure you can get rid of them fast enough to stay safe (alive even).

When the liquid is around 40 C, you will see vapours coming off (including water), slowly.

At 90 C it happens a lot faster, but is not boiling.
Adding a small fan to remove the vapours makes it quicker too.

A possible problem with trying to go faster is 'mechanical entrainment' where the water/acids leave so fast that they take a small amount of your gold compounds with them. Never seen any science showing the actual amounts lost, so no idea if this actually happens to any appreciable extent.

In the end, it's a balance between how much gold you want versus how long you want to wait.

Certainly best to follow the advice given on this site if you're not 100% sure what to do.

Edit:
Clarified which acids won't crystallise by boiling.


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## eaglewings35 (Jan 28, 2017)

Thank you for the very fast replies.
Yes, Lou is one of my favorites on this forum. You can tell from his writing,
he has a great deal of knowledge, smart guy-Ah?
I do have some very clean and clear gold solution... I have nothing but time, I think I will
give it a try.
Do you think the added security of putting a few filters on the mouth of my jar, is a good idea?
This way I can capture any gold that may have gotten out during the EVAPORATING (not boiling) process.

Thanks


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## aga (Jan 28, 2017)

Evaporate slow enough and you'll not lose much.

If you add a filter paper on top, it will evaporate slower, then you'll want to process the filter paper too ...

Up to you to choose between getting 99% of All the gold in 100 years, or lose some and get 90% of the gold a lot sooner.


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## Lou (Jan 29, 2017)

Aga, you are right on my boiling comment and I thank you for clarification. Topher, you are right too. 

I will go into more detail and address some things:

1. I said "boil" because in the right apparatus, you can boil solutions and experience negligible loss, but it is probably best to evaporate first, and then strongly heat the slush of gold crystals to disproportionate the HAuCl4 into gold and gaseous products (which pushes the reaction forward). Note that an excess of chlorine will be required for the gold to transport any significant distance. 

Generally speaking...do NOT boil solutions. Sure, it makes aqua regia go faster on silver items because the nucleation of bubbles on the dissolving material de-scales the AgCl but the downside is that money is surely lost from open beakers!

*Boiling a solution does cause mechanical entrainment of values. A tall container is indicated. 
*

2. Other metals will form firstly their chlorides, then their oxides with strong continued heating. The exceptions are the noble metals, sans silver, all of which are noble because they generally prefer not to exist as oxides. Platinum will contaminate gold, so too will Pd if these solutions are evaporated to dryness. 

If you read above, you will see I mentioned a common procedure. It is called fuming with sulfuric acid. Metal sulfates are generally (except for silver and a few other oddballs) more stable to heat than chlorides, at least in air. The sulfuric basically distills off all of the HCl as a gas and leaves you with your impurities (including silver but excluding lead, barium, and a few oddballs), as soluble compounds and the gold as metallic gold. 

Analytically, you can retard this decomposition phenomenon by the addition of sodium chloride.


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## 4metals (Jan 29, 2017)

> Lou clearly knows his stuff and probably uses 'boil' as a shorthand way to say 'evaporate at an appropriate temperature' ( = a lot less typing !)



Exactly and Amen!

There are many respected authors of technical manuals that use the term boil, yet if it is mentioned here it is a sacrilege worth of stoning. Common sense has to apply to refining or any chemical processing or as one member's signature line puts it, you can't fix stupid!


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## Topher_osAUrus (Jan 29, 2017)

:lol: :lol: 

Well, it's like mentioning the safety stuff repeatedly.. 
The majority here, already know to not taste acids, and wear gloves, and use proper sense... 

But, this is the internet...where common sense is far from common.

So, some new guy may see boil, and proceed to crank it up! -more power! ...Then wonder why he only has a couple grams left of his ounce.

...it is sooo much easier to say boil than "slowly evaporate" though.


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## aga (Jan 29, 2017)

Topher_osAUrus said:


> it is sooo much easier to say boil than "slowly evaporate"


It is, so all we need to do is define a GRF meaning for 'Boil', a bit like the Oxford Dictionary does, then cite that definition if anyone gets confusled.

Normal 'Boil' :
"Heat the thing like mad until it hubbles and bubbles like crazy, steaming and throwing stuff everywhere"

GRF 'Boil':
Suggestions anyone ? 
(too ashamed to make my own before i got even a tiny blob of gold to show for my efforts  )


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## Grelko (Jan 29, 2017)

aga said:


> GRF 'Boil':
> Suggestions anyone ?



Evanish or fade 8) 

http://www.thesaurus.com/browse/evaporate


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## g_axelsson (Jan 29, 2017)

We don't need any new definition for boiling, it would only change that we need to write evaporate when we mean evaporate instead of writing boil and then go on and explain that it doesn't mean boil but evaporate.

What we need is just to take those five extra characters to write evaporate and if we makes a mistake, someone will catch it.

... and redefining boil we need another word for boiling. I suggest we use freeze.
In other words, you have to boil your solution and not freeze it or you will lose some gold. :mrgreen: 

This statement is a statement released by the institute of redundancy institute and is written in newspeek.

Göran


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## upcyclist (Jan 30, 2017)

Or we could just add 'boil' to the forum's profanity filter :lol:


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