auric sodium chloride

[bastinado]

Dear sirs

If i have solution of AuNaCl4 auric sodium chloride

how i would precipitate the gold from this salt ?

 

[goldandsilver123]

Sodium metabisulfite/sulfur dioxide/copperas/sodium nitrite/zinc dust/electrolysis

 

[4metals]

What process did you use to solvate the gold? This is one of those simple sounding questions that can get you into more trouble than necessary because you try something without having fully detailed the process to get to where you are.

Tell us what material you dissolved, and how it was dissolved, and roughly the concentration you have in solution and we can tell you the best way to proceed.

 

[Topher_osAUrus]

What process did you use to solvate the gold? ...

I understand that gold in solution can form complexes, but, can you elaborate on how this one in particular comes about?
For instance, is this something that is common place to happen when doing regular gold processes (AR, is my main concern.-Im assuming it isn't). And, does this complex sodium-gold salt have problems precipitating out of solution with standard methods?(similar to how we should keep ammonia out of our processes, especially with pgm's, as they form a complex that even zinc has trouble reducing)?

How do they make this complex on a grand scale?
How might we accidentally make it?

I skimmed through my books, but they were not very forthcoming with pertinent information.

 

[aga]

I can't even to pretend to know all about this subject, but lots of things can go into forming a 'complex', which is basically a type of stable arrangement of atoms which may or may not have exactly 'reacted' in the formal sense (i.e. formed electron bonds).

An easy to make and beautiful coloured one is tetraamminecopper(II) sulfate - just add ammonia to a concentrated solution of copper sulphate.

With a Refiner's random solution of metals and acids, if you add anything that has not already been extensively researched, there is a chance of making one or more 'complexes' which contain the atoms you're looking for.

The big thing is that complexes do not necessarily behave the way you want, e.g. precipitate with SMB etc.

 

[goldandsilver123]

What process did you use to solvate the gold? ...

I understand that gold in solution can form complexes, but, can you elaborate on how this one in particular comes about?
For instance, is this something that is common place to happen when doing regular gold processes (AR, is my main concern.-Im assuming it isn't). And, does this complex sodium-gold salt have problems precipitating out of solution with standard methods?(similar to how we should keep ammonia out of our processes, especially with pgm's, as they form a complex that even zinc has trouble reducing)?

How do they make this complex on a grand scale?
How might we accidentally make it?

I skimmed through my books, but they were not very forthcoming with pertinent information.

NaAuCl4 It's just gold dissolved in aqua regia that is added NaCl.

HAuCl4 + NaCl -> NaAuCl4 + HCl (HCl being lost as a gas)

It can be formed with poor's man aqua regia.

But in a solution with water they are as [AuCl4]- and Na+, so normal aqueous reduction methods works.

 

[4metals]

The reason for asking for details is the OP's question involves a specific species of gold salt. Why would one add salt to aqua regia if aqua regia would dissolve the gold without the salt? My original thought was that Hydrochloric Acid and Sodium Chlorate were used to digest finely divided gold.

If Hydrochloric / Sodium Chlorate was used, there would be no prerequisite to denox the solution. But as I said in my post above, there is no sense in speculation on our part until we have more details from the OP concerning his process. Simple question actually?

 

[bastinado]

OK

I have dissolved my gold in relatively large amount of Hcl 30 % concentration then and bleach ?( 5% Naoh + 5% Naocl ) and then i have add some of SMB , and when i found no gold precipated i have add some of H2O2 , then some of sodium thiosulfate and fainally lettile ammount of gold precipated with some of sulfer

the solution color is still yellow and other one green with golden yellow

the green solution becouse is dissolved the IC small wires in the Acid bleach (some of copper in the solution)

so i assumed some or may be the most of the gold have make complex with Nacl

Nacl have formed when i have added the hcl to bleach or when i add Na2s2o5 in thais mixture

 

[Lino1406]

Thiosulfate - Na2S2O3 - reacts violently with H2O2, means they act opposite

 

[bastinado]

I see

I have H2so4 as result of adding Na2s2o3 + h2o2

really i don't know what is the chemical form of my gold in this solution
May be AuNaCl or Auso4 or somtyhing more complex or what i have dropped is every thing ?!!!

 

[Lino1406]

Gold form in solution = Au+++

 

[goldandsilver123]

Heat to 80 °C keep in this temperature for 30 min then do a stannous chloride test.

Then if doesn't show anything, evaporate to 10% of the volume and do it again. (without boiling it's better)

If it doesn't show anything with the concentrate, you had too little gold to start with.

 

[aga]

... and bleach ?( 5% Naoh + 5% Naocl ) and then ... some of SMB ... add some of H2O2 , then some of sodium thiosulfate ...

Truly and Honestly, it is better to follow a Known-To-Work process than throwing in many reagents and hoping for the best.

The materials you start with are an unknown quantity/composition to begin with.

Add in more unknown weights of chemicals of unknown purity and what is the result ?

Complete confusion in both the chemical mix and anyone trying to work out what has been formed.

I'm still trying to recover just the metals (not even the gold yet) from a similar mess i made Weeks ago.

 

[Topher_osAUrus]

I got a little more confused than clarified after those replies..

So, simply adding salt to an AR dissolve of gold will complex it to NaAuCl3?

In that case, what does the gold complex end up being when dissolving gold with bleach and hcl? And it is creating salt in the reaction, which would have sodium ions floating around in it, right?

And, what if a guy starts off with bleach+HCl and realises its too slow for thick foils, then adds a few mL's of nitric?

In these examples, is this sodium complex being formed? Or am I way off here?

 

[goldandsilver123]

So, simply adding salt to an AR dissolve of gold will complex it to NaAuCl3?

Yes and No, and it's NaAuCl4.

When you have a solution of NaCl you don't have NaCl in solution, you have Na+ and Cl- and what's keeping them apart is water, which have a high dielectric constant and can separate ions pretty well.

A solution of aqua regia (in excess) with gold in it will be something like this:

H+ + NO3- + Cl- + AuCl4- + H2O

If you add NaCl to it you will have this:

Na+ + H+ + NO3- + Cl- + AuCl4- + H2O

This is because all of the are soluble. If you heat it until dryness HCl will be lost as a gas, HNO3 too and you will end up with NaAuCl4 solid.

In that case, what does the gold complex end up being when dissolving gold with bleach and hcl? And it is creating salt in the reaction, which would have sodium ions floating around in it, right?

If the excess bleach is destroyed by boiling and you have excess HCl, if you dry everything you will end up with NaAuCl4.

And, what if a guy starts off with bleach+HCl and realises its too slow for thick foils, then adds a few mL's of nitric?

If it's not added enough NaClO to give Na+ them it's a mixture os HAuCl4 and NaAuCl4.

But in solution if it's NaAuCl4 or HAuCl4 you have AuCl4- ion, that reduces normally with SMB and etc


If one uses Poor's man aqua regia, it's the same thing that's created if dried.

3 NaNO3 (salt peter) + 6 HCl + Au -> 3NO2 + AuCl4- + 3 Na+ + 3 H2O + 2 Cl-

Or

3 NaNO3 + 6 HCl + Au -> NaAuCl4 + 2 NaCl + 3 H2O + 3 NO2

But since it's a aqueous solution it's as AuCl4- and can be reduced with normal reductants.

If I didn't explain clearly you can pmsg me, don't know if it's getting out of topic.

 

[aga]

I got a little more confused than clarified after those replies

Unfortunately the Chemistry is quite complicated, which is why Hoke's instructions are a work of sheer Genius - she knew loads about the specific details, then wrote a book that made it easy for non-chemists to do.

The specifics of the chemistry are well over my head for sure.

goldandsilver123 explains it well in the post above.

Details in things like "bleach is destroyed by boiling" end up with interim steps, as the bleach (NaOCl) disproportionates into NaOCl3 and NaCl in the process, which are free to react until all the water is boiled off.

As these are all ionic compounds, their components (e.g. Na⁺, Cl^-) remain in solution with the water, as water is also partially ionic in nature.

It is pretty much off-topic, as it's delving into the Grey Magic, aka Inorganic Chemistry.

Dark Magic is Organic Chemistry.

Black Magic is Organometallic Chemistry where they extract all the gold from a rabbit in 2 milliseconds using just a potato and a 5 cent coin, without the rabbit even noticing.

 

[Topher_osAUrus]

Thank you guys for elaborating it so a simpleton such as myself can understand. :mrgreen:

So, basically whenever there is a free Na+ in situ, it will bind to the AuCl4 from the HAuCl4, and then give the free H+
And then, if it were heated to dryness, it would leave a sodium-gold complex salt.

Which is a point that Lou made in another post, here-
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=24266
Where he says the decomposition phenomenon is retarded by the addition of salt.

All the pieces of the puzzle have come together for me now (at least I think so :roll: )

 

[bastinado]

i think the best thing to do is to dry the solutions totally and then incinerate the salts

and re dissolve first in water

and the remain i would dissolve with acid and bleach but in moderate quantities

 

[g_axelsson]

i think the best thing to do is to dry the solutions totally and then incinerate the salts

and re dissolve first in water

and the remain i would dissolve with acid and bleach but in moderate quantities

I disagree, incinerate a gold chloride solution would lead to losses of volatile gold chloride.

The first thing to do would be to make stannous and test the liquid to see if there are any gold in solution. If the liquid doesn't contain any detectable levels of gold then there is no need to try to extract any more gold from it, then it can be treated as waste and disposed properly.

Why not follow Goldandsilvers advice above and test what you have?

Göran

 

[bastinado]

i Failed to dissolve tin in less then 30 % Hcl

may i add H2O2 to the Hcl to dissolve the tin ?