what's in my Auric Chloryde?

[Le Mineur Urbain]

hey everyone!!
So I had 35 pounds of these boards (see picture) which I processed in A/P, recovered the foils and then dissolved in acid/bleach,
I've done this many times but this time it turned out red (see picture). Any idea why? what it is? and what reaction can I expect when I add SMB to drop the gold??
Thanks!!

 

[Eamonn]

Hi Le Mineur Urbain
It has the colour of a gold colloid but you wouldn't normally get one with HCl and bleach. You can check this if you shine a lazer pointer through the solution and you see the beam in the solution you have a colloid.

Eamonn

 

[g_axelsson]

Welcome to the forum! 8)

Gold colloid seems like a good guess.

What does stannous test show?

If it shows barren, then your gold is already reduced out of solution as a colloid.

As a test, take a small sample and add more bleach. This should dissolve the gold again, taking it back into a normal yellow solution.

This could be the result of having tin chloride (stannous chloride) in solution when trying to dissolve the gold. The bleach would dissolve the gold while the stannous chloride reduce it back out again as a colloid. If the bleach runs out before the stannous you would end up with a colloid.

Adding SMB to this would produce gold only if there is any gold in solution. Even if there is, some gold might be in colloidal form and then it won't come down with the other gold.

Please, let us know how it goes, this is an interesting problem and could be a good example for other with similar problem.

Göran

 

[Le Mineur Urbain]

I'm out of stannous chloryde, making a new batch right now... I put the smb and it dropped properly although the solution is still yellowish,but when I first added it, the red color disappeared to turn yellow as it originally should've been, then turned dark as I hoped. I'll keep it aside to test once the stannous is ready. When I filtered the foils I noticed some kind of black powder in the acid, I was told it was either, iron, antimony or palladium. I doubt its palladium since it all came from clean boards as on the picture. thanks for answering!

Welcome to the forum! 8)

Gold colloid seems like a good guess.

What does stannous test show?

If it shows barren, then your gold is already reduced out of solution as a colloid.

As a test, take a small sample and add more bleach. This should dissolve the gold again, taking it back into a normal yellow solution.

This could be the result of having tin chloride (stannous chloride) in solution when trying to dissolve the gold. The bleach would dissolve the gold while the stannous chloride reduce it back out again as a colloid. If the bleach runs out before the stannous you would end up with a colloid.

Adding SMB to this would produce gold only if there is any gold in solution. Even if there is, some gold might be in colloidal form and then it won't come down with the other gold.

Please, let us know how it goes, this is an interesting problem and could be a good example for other with similar problem.

Göran

 

[Professor]

Chloroauric acid is yellow, but if the pH is high the sodio gold will impart a redness to the solution. Try adding hydrochloric acid to see if the sodium chloride precipitates leaving a yellow solution. Yet colloidal gold is a prime suspect. This is a photo of colloidal gold taken from the internet.

 

[g_axelsson]

Chloroauric acid is yellow, but if the pH is high the sodio gold will impart a redness to the solution. Try adding hydrochloric acid to see if the sodium chloride precipitates leaving a yellow solution.

Professor, I'm not sure you are in the position to advise others on refining.

By the way, where did the sodium chloride come from?

Göran

 

[Professor]

From the bleach

 

[g_axelsson]

Why would it precipitate? Bleach isn't that loaded with sodium so it would saturate the solution.
Sodium chloride is soluble in water.

Göran

 

[Professor]

Sodium chloride is quantitatively determined by measured additions of Hydrochloric acid. It is not soluble in strong hydrochloric acid. Something more; citric acid is often added to bleach. It would cause a colloid to form. Also sodium gold chloride decomposes at 100 C and also will cause a colloid to form if the pH is too high.

 

[nickvc]

Your mistaken, citric acid causes no reaction in gold solutions, ascorbic acid will precipitate gold from a gold chloride solution, it will not make a colloid.

 

[Topher_osAUrus]

Sodium chloride is quantitatively determined by measured additions of Hydrochloric acid. It is not soluble in strong hydrochloric acid. Something more; citric acid is often added to bleach. It would cause a colloid to form. Also sodium gold chloride decomposes at 100 C and also will cause a colloid to form if the pH is too high.

Maybe not soluble in 99% HCl

But muristic acic, that is usually around 30%, is 70% water... Now i know sodium chloride.....salt.... IS soluble in water, AND there is quite a bit of water in HCl, so unless he did 1:1 bleach hcl, i doubt its a contributing factor.

Salt is used in the ssn leach and doesnt seem to give those that try it these kind of problems.

And if that much bleach was used, the solution would almost certainly be borderline basic.

But, im uneducated, so hopefully one of our chemists or pro's can clarify for me.

Its hard to continue to gain knowledge TO get educated when some people choose to pepper in pieces of misinformation. But, i guess when youre a tenured professor, infallibility rides hand in hand with that (apparently)

It (this misconstrued misinformation) may end up getting someone seriously hurt down the line.

 

[Anonymous]

Why would it precipitate? Bleach isn't that loaded with sodium so it would saturate the solution.
Sodium chloride is soluble in water.

Göran

Goran I completely agree with your comments apart from one thing. Ive seen NaCl precipitate from a solution of HCl/Sodium Hypochlorite. Usually when you've not added any water to the solution prior to dissolving the gold. What it has never done for me is turn a solution red. 8)

I'd go with colloidal gold too. Very low concentrations of colloidal gold are red. I found that out when talking to Deano about some redness I had in washing up water that I had used to clean some spoons I had used for stannous tests so all credit goes to him for that knowledge.

Jon

 

[g_axelsson]

My bottle of bleach contains 27g sodium hypochlorite per liter (kilo actually), I don't think it would be enough to precipitate any sodium chloride in any situation I run into. Maybe with a lot of evaporation it could be an issue.

The original problem was a red solution of gold, not precipitating sodium chloride. I still don't see the relevance of adding additional HCl so NaCl would precipitate. In which way would that solve the original posters problem? And he already found a solution, although I still suspect that he got some colloidal gold in his yellow solution.

If the color of the solution is coming from high pH then there is no need for adding enough HCl to precipitate NaCl, a small addition would work to adjust the pH into acidic conditions and turn the color back into yellow (if it is red at higher pH, haven't found a picture of it).

I think that the fact that SMB reduced the gold chloride tells us that the solution was acidic. My experience is that SMB doesn't work in neutral solutions, there should be some free acid to break it down and release the SO₂ that reduces the gold.
Yet again, my experience is only once with gold chloride dissolved in pure water, not at basic pH levels so I can't say anything about that. The gold refused to precipitate until I added a bit of HCl, so now I always drop gold from acidic solution and I've never had any problems since then.

Göran

 

[Geo]

Depending on the concentration of gold in solution, the color of auric chloride can be bright red to pale yellow. Auric chloride crystals are brilliant red. Gold solution can be orange. Any combination of red and yellow. Sodium hypochlorite decomposes to sodium chloride. The reason sodium chloride is not any real problem is because it is so soluble in water. If it precipitates for whatever reason, it can be dealt with by using water rinses or by adding water to the solution. Debating table salt is really a non-issue.
As far as the OP's original question, there's no way for any one of us can tell you what is in your solution by looking at a picture. It could be water and food coloring. Any answer you get here would be a guess at best as far as what is in the solution. Palladium makes for a red solution so it could be a combination of gold and Pd. You could have helped yourself get a better answer by adding a picture of the stannous chloride test.
If it is a colloid of gold, it can be dissolved by adding more oxidizer or broken by adding a little sulfuric acid and boiling the solution until you get a color change.

 

[Professor]

Your mistaken, citric acid causes no reaction in gold solutions, ascorbic acid will precipitate gold from a gold chloride solution, it will not make a colloid.

Spend some money. Get an education. https://www.researchgate.net/publication/229236778_Electrochemical_evaluation_of_citrate_adsorption_on_Au111_and_the_stability_of_citrate-reduced_gold_colloids

 

[Anonymous]

Your mistaken, citric acid causes no reaction in gold solutions, ascorbic acid will precipitate gold from a gold chloride solution, it will not make a colloid.

Spend some money. Get an education. https://www.researchgate.net/publication/229236778_Electrochemical_evaluation_of_citrate_adsorption_on_Au111_and_the_stability_of_citrate-reduced_gold_colloids

You're really not grasping the idea of how to deliver things are you. Whether you're right or wrong is irrelevant if you come across as a knob.

 

[nickvc]

Your mistaken, citric acid causes no reaction in gold solutions, ascorbic acid will precipitate gold from a gold chloride solution, it will not make a colloid.

Spend some money. Get an education. https://www.researchgate.net/publication/229236778_Electrochemical_evaluation_of_citrate_adsorption_on_Au111_and_the_stability_of_citrate-reduced_gold_colloids

If I'm wrong then please elucidate me, I have used ascorbic for many years to precipitate gold but have never put citric acid into an AR solution and could find no good reason to do so.

 

[rewalston]

Your mistaken, citric acid causes no reaction in gold solutions, ascorbic acid will precipitate gold from a gold chloride solution, it will not make a colloid.

Spend some money. Get an education. https://www.researchgate.net/publication/229236778_Electrochemical_evaluation_of_citrate_adsorption_on_Au111_and_the_stability_of_citrate-reduced_gold_colloids

You're really not grasping the idea of how to deliver things are you. Whether you're right or wrong is irrelevant if you come across as a knob.

I'm beginning to think that the door needs to hit the knob. Just my humble opinion.
Rusty

 

[butcher]

Citric acid has been used to make colloidal gold, but that is something we normally try to avoid. the Citric acid reduces the gold, but the gold stays in solution.
There may be more steps to it, its been quite some time since I read about that method of making colloidal gold.
http://www.veterinaryworld.org/Vol.7/Feb-2014/6.pdf



Professor, you sure know how to wear out a welcome don't you, but I suspect that is part of your reason for you showing back up here again after all of this time.

You were warned about getting along, apparently you ignored it, you know the rules here and what is expected of members, you also know that your coming here to cause trouble will not be accepted.
Have a good day sir. bye

I banned the professor, I suspect this is not the first time he has been banned, and probably not the last we will see of him. It seemed his whole purpose was to make trouble, and prove he is smarter than anyone here.

 

[butcher]

I just read my email (after reading the above post).
Here is the email professor sent me (apparently in reply to what I said to him in the other thread warning him to improve his behavior).

I was warned that this forum had gone bad. It seems that jealousy is prevalent. What happened? My guess is that donations were made that allows some to be spiteful, rude and judgmental. There is no need to banish me from the forum. I suspect that you will anyway. If you do banish me, I will return to the ATM and withdraw the donation as cash. It seems that one can't be intelligent and experienced without being berated by the less educated. FYI gold chloride will cement onto platinum. However the reaction is very slow and the color of the gold clad platinum is black. I came onto this forum seeking some help and I got it. I gave some help in return. I will not be your whipped dog and whimper whenever you snap. Yes, my education and experience exceeds even Miss Hoke. She stated plainly that her book did not include ores, only scrap. If you want to read more of my very good advice, then inform those others to just get off my back. I actually think that this will be the last time you allow me on this forum. Jealousy! :x


What can I say? I did not get a good education. I guess I am jealous I am not that smart. Oh well I can learn.