# HCl-Cl percipitate problem



## Anonymous (Dec 25, 2007)

i used the HCl-Cl method.on approx 6 grams of gold foils.it desolved in a short time.But I cannot get the gould to drop with the smb.any ideas?please help


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## Noxx (Dec 25, 2007)

You must neutralise it first 8) 
Just add some urea untill it stops bubbling.


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## Anonymous (Dec 25, 2007)

thank you for the quick response.Is it possible to add urea and try again?


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## Anonymous (Dec 25, 2007)

when I read the mix for the Muratic acid and bleach.It said no urea.I was wondering if you knew what makes it require urea.also i have some effort in the gold i melted with that solution.so i have a flask full of mixture thats ful of gold and SMB thats nor dropping any PM,s. Can I rejuvenate it and try again with out losing gold.?Thank You for your time
Rich :roll:


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## lazersteve (Dec 25, 2007)

Rich,

Welcome to the forum.

The HCl-Cl method does *not* require Urea. Your problem stems from excessive chlorine in the solution. 

This occurs when you use more bleach than is required to dissolve the gold foils. You'll get the hang of how to judge the amount of Clorox needed as you perfrom the reaction more often. 

You will soon come to find out that it doesn't take much. The real trick is adding the Clorox slowly and in very small increments to generate just enough chlorine to dissolve the foils. Stirring until no more fizzing is visible is how I guage this reaction. I typically let the reaction sit for a few minutes after the fizzing stops and stir one last time to confirm no more reaction occurs.

If you are seeing and smelling lots of chlorine gas then you are adding way to much Clorox. 

There are a few ways around your problem at this point. 

1) Put the beaker in direct sunlight to destroy the excess chlorine.

2) Gently heat the beaker in a safe area and drive the excess chlorine gas out of the liquid.

I hope this helps.

Steve


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## Anonymous (Dec 25, 2007)

Im just curious about the smb.does it get neutralized?
I want to thank you guys.Steve I have visited your site often.(not that you could tell it from my results)
I,ve noticed the members of his forum are very helpful not to mentioned informed.Its nice when something works.
I started getting interested in the recovery and refining because I had been dabbling in the recycling business.I'm trying to find out what recyclable material is in my inventory of gear.
If anyone wants to take a peek its www.etron-trade.com . I have alot thats not loaded yet.Just started site.
Anyway Steve, I will see what I can do about that chlorine.
Thanks again
Rich


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## aflacglobal (Dec 25, 2007)

Link is broken. It has an extra i added at the end. :arrow: www.etron-trade.com

That looks like it will be a cool site you are working on. Welcome to the forum.


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## lazersteve (Dec 25, 2007)

I fixed the link for you. When typing websites in the body of a post be sure to put spaces on either side of the web address.

Steve


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## aflacglobal (Dec 25, 2007)

Their seems to always be some confusion about neutralizing of the hcl-cl method.

Now in the hcl-cl method the neutralization of the solution is by the evaporation of the excess chlorine from the solution. Which is volatile and easily dispersed from the solution. Even when an excess is added it is easily removable with light or evaporation.

Now in the aqua regia method you must neutralize the excess nitric with urea. Is this because that the nitric acid is not as volatile and easily dispersed as the chlorine is in the hcl-cl method so we have to add a catalyst ?

Given enough time will the nitric neutralize itself in the aqua regia method or will the gold self precipitate with the trash in the solution before that point ? 

Without getting rid of the excess cl from the hcl-cl method or nitric from the AR method your gold will just redissolve into the solution. Once the ion count is saturated you must remove the extra ions or they will keep working ? But once they are removed and the solution is neutral you can then add the smb which without the excess ions will then form complexes with the gold in solution to cause them to become complex molecules and precipitate from the solution.

Am i close ?


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## Noxx (Dec 25, 2007)

Oh dam I taught urea was needed...

But when I think about it, no NOx are in the process...


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## aflacglobal (Dec 25, 2007)

OK. When we add the urea to the Nitric in the AR method what we are doing is adding a base to this solution, and this will neutralize the PH of the solution. By neutralizing the PH of the solution we have lowered the concentration of H3O+ ions because pH is dependent on ionic activity.

Once this is complete we can add the smb which will form bond complexes with the Pm's. If it were not neutralized first then the excess ions being stronger in nature would not allow the smb to form bonds within the solution. It would keep the gold in solution. Dam bully ions.  But because we have neutralized the excess ions in the solution then the strength of the bonding force from the smb ions then become greater than that of the solution.

Someone stop me. :lol:


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## Anonymous (Dec 26, 2007)

keep that kinda info coming
Rich


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## Lino1406 (Dec 29, 2007)

What for?


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