Help with refining 10k to 24k gold

[Will]

I am a new member. I am trying to refine 84g of 10k gold. I melted the gold and poured it into water to get it into smaller pieces. I the put the gold in 3oz of nitric, left it for a couple hours and then added the nitric acid to 9oz of hydrochloric acid. We then let it sit for 40 hours. It doesn't look like much has happened. There is still big chunks of metal in the solution, although it does look Grey instead of gold. The solution is green in color but with chunks. After going over the process I noticed that the bottle of hydrochloric acid said 4% on it. It was purchased from gold refining supplier so I didnt think anything of it. I believe the hydrochloric should have been a higher %. I have some Kleen Strip Green muriatic acid and I believe it is either 20% or 31%. It doesn't say on the bottle.
Was the hydrochloric to low of %? Can I add the muriatic to the AR solution already made to bring the hydrochloric % up? Any help would be greatly appreciated.
Thanks in advance.
Will

 

[Will]

Was I supposed to start with a solution of 3parts hydrochloric and 1part copper chloride 1st? I believe that this process was for separating computer fingers followed by the process with the AR solution. We started with just 10k gold. Please advise as to what to do as I am brand new with this.
Thanks in advance
Will

 

[Yggdrasil]

Was I supposed to start with a solution of 3parts hydrochloric and 1part copper chloride 1st? I believe that this process was for separating computer fingers followed by the process with the AR solution. We started with just 10k gold. Please advise as to what to do as I am brand new with this.
Thanks in advance
Will

Welcome to us.
I have no time now.

But study these and I post something later:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

 

[goldshark]

OK, pretty simple really, you need to reduce the the Gold to 6K, then put it in Nitric . 10 k doesn't allow full exposure of Au/Ag atoms to do the job of dissolution. Re-heat in crucible to melt temp, add appropriate amount Ag (Silver preferred over Copper ) to reduce to 6K. This is called in quarting. Many threads on the subject here.

 

[anarxi]

I am a new member. I am trying to refine 84g of 10k gold. I melted the gold and poured it into water to get it into smaller pieces. I the put the gold in 3oz of nitric, left it for a couple hours and then added the nitric acid to 9oz of hydrochloric acid. We then let it sit for 40 hours. It doesn't look like much has happened. There is still big chunks of metal in the solution, although it does look Grey instead of gold. The solution is green in color but with chunks. After going over the process I noticed that the bottle of hydrochloric acid said 4% on it. It was purchased from gold refining supplier so I didnt think anything of it. I believe the hydrochloric should have been a higher %. I have some Kleen Strip Green muriatic acid and I believe it is either 20% or 31%. It doesn't say on the bottle.
Was the hydrochloric to low of %? Can I add the muriatic to the AR solution already made to bring the hydrochloric % up? Any help would be greatly appreciated.
Thanks in advance.
Will

Hello.
yes, hydrochloric acid should be about 13%.
You have more than an ounce of pure gold there, it makes sense to spend money on normal reagents and read the labels more carefully.
In addition, heating is required.
and nitric acid must be added little by little.
To dissolve your material you will need about 230 ml. nitric acid
(84 grams of 10 carat material is about 40% pure gold, which requires 1 ml/1 gram to dissolve.
the remaining 60% is subject to a 1/5 ratio.

 

[anarxi]

OK, pretty simple really, you need to reduce the the Gold to 6K, then put it in Nitric . 10 k doesn't allow full exposure of Au/Ag atoms to do the job of dissolution. Re-heat in crucible to melt temp, add appropriate amount Ag (Silver preferred over Copper ) to reduce to 6K. This is called in quarting. Many threads on the subject here.

it looks like some of the gold has already gone into solution
too late to change horses midstream...

 

[Will]

Hello.
yes, hydrochloric acid should be about 13%.
You have more than an ounce of pure gold there, it makes sense to spend money on normal reagents and read the labels more carefully.
In addition, heating is required.
and nitric acid must be added little by little.
To dissolve your material you will need about 230 ml. nitric acid
(84 grams of 10 carat material is about 40% pure gold, which requires 1 ml/1 gram to dissolve.
the remaining 60% is subject to a 1/5 ratio.

Thanks for replying. Just add 230ml of nitric to my solution that I already have? Do I not need to add hydrochloric. Or are you saying I need to make a new AR solution with 230ml of nitric and 690ml of hydrochloric? If I need the hydrochloric, can I use the muriatic acid that I have on hand instead of the hydrochloric. Thanks for your help. I am real interested in learning this process.

 

[anarxi]

did you heat the solution?
try warming it up first.
degrees up to 80 Celsius.
Leave 2/3 of the reserve in the glass in case it foams.
but it is more practical to put this aside for now and read what the moderator suggested to you.
You have a lot of gold, so it looks like this:
“enter the water without knowing the ford”

 

[Yggdrasil]

Thanks for replying. Just add 230ml of nitric to my solution that I already have? Do I not need to add hydrochloric. Or are you saying I need to make a new AR solution with 230ml of nitric and 690ml of hydrochloric? If I need the hydrochloric, can I use the muriatic acid that I have on hand instead of the hydrochloric. Thanks for your help. I am real interested in learning this process.

If you do as you are told this will go fine.
But you have started out the wrong way.
First pour your Gold bearing Liquid into a container and set it aside for now.
Do you have testing acids or access to a XRF?

 

[Martijn]

Thanks for replying. Just add 230ml of nitric to my solution that I already have? Do I not need to add hydrochloric. Or are you saying I need to make a new AR solution with 230ml of nitric and 690ml of hydrochloric? If I need the hydrochloric, can I use the muriatic acid that I have on hand instead of the hydrochloric. Thanks for your help. I am real interested in learning this process.

Let's keep it at learning to begin with. As soon as you feel you understand it, ask us if your plan is any good before you try anything.
Plan it on paper and don't dive into it.
As anarxi first said: 'heating is required', it has some nuances to it to do it right.

It all sounds really simple, and can be if performed correctly.

 

[4metals]

I am trying to refine 84g of 10k gold. I melted the gold and poured it into water to get it into smaller pieces.

You should have added silver to the melt and brought the overall karat down to 6 karat.

I the put the gold in 3oz of nitric,

1 part Nitric (68%) 2 parts distilled water is what is best for the parting process. And heat is a necessity. But so far what you did isn't terrible.

left it for a couple hours and then added the nitric acid to 9oz of hydrochloric acid.

This is where you went downhill fast! The parting acid (even with 10 karat) will dissolve out base metals and silver. It is most effective when you have inquarted with silver. Your mistake here was adding the nitric to hydrochloric. (even the dilute hydrochloric). You should have decanted the nitric acid solution and rinsed the insolubles. If you had done this instead of adding the nitric to the solution with hydrochloric you would have had a more concentrated gold absent of Silver and base metals and the aqua regia process will work well.

There is still big chunks of metal in the solution, although it does look Grey instead of gold.

The gray is silver chloride which encrusted the remaining metal and stopped the reaction.

To recover the gold from the gray mass you should soak it in warm ammonia to dissolve the silver chloride and then remelt the metal (which should no longer be gray) and add silver to get close to 6 karat gold. Then you can follow the instructions above to refine it after parting.

Add Hydrochloric Acid to the ammonia solution and the Silver will drop out as Silver Chloride which can be recovered later.

The original solution will have some Gold and some Silver in it and will be best handled by filtering out the Silver Chloride and the rest of the solution is processed by cementing it on copper. (if a stannous chloride test indicates there is gold in the solution)

 

[goldshark]

Thanks for replying. Just add 230ml of nitric to my solution that I already have? Do I not need to add hydrochloric. Or are you saying I need to make a new AR solution with 230ml of nitric and 690ml of hydrochloric? If I need the hydrochloric, can I use the muriatic acid that I have on hand instead of the hydrochloric. Thanks for your help. I am real interested in learning this process.

Muriatic = Hydrochloric. In other words, they are the same.

 

[4metals]

Muriatic acid is typically 20º baumé which is 31.45% hydrochloric acid solution. The industrial grades which are typically greenish in color are the same acid but not as highly refined.