Anyone came up with a technique or process for watch bands ? _reverseAR_

[g_axelsson]

Thanks 4metals so in essence, if you were using stainless steel products with a much larger percentage of gold present then would the possibility of heat being generated increase with the gold content? Assuming of course that I'm reading what you are saying correctly and not interpreting it the wrong way

This process is great for lots with a large quantity of stainless containing a relatively small percentage of metal for selective dissolution. The ratio of Nitric to Hydrochloric is so skewed from normal aqua regia that mixing it up for lots with a high percentage of dissolvable metals would require more acid than a normal aqua regia digestion and it is doing so with the acid you need to get rid of to precipitate the values.

This excels for stainless steel scrap with under 10% aqua regia soluble metals in it. It is truly a niche solution to a refining problem.

The same process works for gold on aluminum. The nitric acid passivated the aluminum surface when the gold was dissolved.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=19177&start=20#p194541

Göran

 

[Richard NL]

So a small guy may say that's a lot of nitric, and it is, but it performs the necessary reactions.

The gold is in the filtered solution with a lot of nitric. The nitric needs to be neutralized before the gold will drop out. Sulfamic acid is the way to do this. It is imperative that you keep track of exactly how much 70% nitric you used to start. For every milliliter of nitric you started with add (need I say cautiously) 1.5 grams of sulfamic acid.

Then drop the gold with your precipitant of choice.

So now you have to decide is the use of more nitric worth saving your hands! All refining techniques involve trade-offs, this one requires nitric which does not come easy to some smaller refiners.

Ah, but then the issue is how do you get the gold out from all that nitric acid?
Sure, it can be extracted with solvent, with resin, or certain reducing agents but they all have their pitfalls.

IMHO,
Is it not easier to get rid of the unused HCl.
With "Harold's added gold button technique" to use up the free HCl.
The precipitation of gold will be dirty.
But you can re-use all the nitric for the next aqua regia after gentle warming to get rid of possible excess SO₂, and save a lot off Sulfamic acid.

Best regard,
Richard.

 

[g_axelsson]

IMHO,
Is it not easier to get rid of the unused HCl.
With "Harold's added gold button technique" to use up the free HCl.
The precipitation of gold will be dirty.
But you can re-use all the nitric for the next aqua regia after gentle warming to get rid of possible excess SO₂, and save a lot off Sulfamic acid.

Best regard,
Richard.

I don't think it will work, we still have the Cl in the AuCl₃ that would combine with nitric acid and create aqua regia.

When we denox a solution we get rid of not just the nitric acid but also the nitrate salts. When all nitrate ions are gone the gold can not be dissolved. But the only way to remove chloride ions that I know of is to add silver nitrate and precipitate it as silver chloride. In that case we would have created a gold nitrate solution and that's a beast I have no idea of how it would react, or even if it would be stable at all.

Göran

 

[Richard NL]

I had to dig a little deeper in the forum.
http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=6026&start=90#p73485 ending with post February 12th, 2011, 3:54 pm

And http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=49&t=1415

As far as I understand it, there is a chloride used in making (using HCl) gold chloride, we have in this case no gold nitrate but a gold chloride in a nitrate solution.
As we precipitate the gold chloride in a nitrate solution we want a diluted solution and colder temperatures, so therefore the interaction between the metallic gold and the newly created chloride are minimal.
For the part of the metallic gold that it comes into contact with the chloride will dissolve again into the liquid and precipitate again(in contact with SO₂gas).

In a normal aqua regia, there will be no reaction with the liquid medium, a chloride in a chloride solution.
In this case, however, the consequence is that we would like to have menial chloride in this mixture/liter.
In precipitating the gold we create a solution of aqua regia.
3NaHSO3+2AuCl3+3H2O=3NaHSO4+ 6 HCl +2Au

If we are looking at this post: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=10799#p107942 then it is clear why we don't want this, but given the circumstances it's ok i guess.
The little bit gold chloride which remains in the nitric acid will be locked up until you re-use the nitric acid for aqua regia.


I do not know how to make gold nitrate, perhaps with electrolysis/nitric acid+........

I hope you all understand what i mean :|

Best regard,
Richard.

 

[SinisterGenuis]

Hello all, I am new and have a few questions about the RAR process and it making stainless watch bands easier to process. I hope no one is bothered by me resurrecting an old thread(some of my other forums get irked by that). First, at the point where all of the desired material has gone into solution is it a visually and very apparent moment where the stainless may now start to be attacked? and along with the gold all other base metals go into solution as well except for the stainless correct? If I'm not mistaken I saw here where it is mentioned the nitric has to be neutralized before the gold will drop out? I may be mistaken on that because I noticed another poster mentioning about not wasting acid for future use. When you precipitate base metals will drop out with the gold and then just perform the normal hot dilute Nitric, then aqua rigia. Same as if it were just a copper or silver GF piece you started with.

Thanks so Much SG

 

[Yggdrasil]

Hello all, I am new and have a few questions about the RAR process and it making stainless watch bands easier to process. I hope no one is bothered by me resurrecting an old thread(some of my other forums get irked by that). First, at the point where all of the desired material has gone into solution is it a visually and very apparent moment where the stainless may now start to be attacked? and along with the gold all other base metals go into solution as well except for the stainless correct? If I'm not mistaken I saw here where it is mentioned the nitric has to be neutralized before the gold will drop out? I may be mistaken on that because I noticed another poster mentioning about not wasting acid for future use. When you precipitate base metals will drop out with the gold and then just perform the normal hot dilute Nitric, then aqua rigia. Same as if it were just a copper or silver GF piece you started with.

Thanks so Much SG

Welcome to us.
You just have to watch the process, when the reaction stops it is finished.

But if you are going to do chemical processing we want you to study these links:

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/

 

[SinisterGenuis]

Welcome to us.
You just have to watch the process, when the reaction stops it is finished.

But if you are going to do chemical processing we want you to study these links:

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/

Thanks so much I have read all and have no interest in ores(unless the source is free and plentiful) so no worries there, and I will re-read several times both "dealing with waste" and "cement it out". I have owned Hokes book for sometime now, but have solely focused on processing karat scrap via inquarting or Processing Gold Vermeil. I had done the tops of watch bands but absolutely hate the seperating process from the stainless. Actually the mens bands not so bad, but many of the ladies bands I don't like. So the RAR process found in this thread intrigued me greatly.

 

[cejohnsonsr1]

Unfortunately, the mechanical separation of the tops is the best way to process gold filled or karat watch bands. It’s tedious and time consuming, but yields better results and uses a lot less acid and so produces far less waste to be processed.

 

[SinisterGenuis]

Unfortunately, the mechanical separation of the tops is the best way to process gold filled or karat watch bands. It’s tedious and time consuming, but yields better results and uses a lot less acid and so produces far less waste to be processed.

So as I mentioned previously my 2 go-to processes thus far have been (Karat scrap) using inquarting, and gold Vermeil. Haven't really done any stainless backed bands other than pulling the top caps off and doing them by themselves, but have a lot of bands I've been stacking up over time that are more entailed then just popping tops off. So I haven't tried this yet but was going to do a test run with a single band and see what happens. If the Nitric boil will release the base/filler metal from the gold foils and also passivate the stainless, wouldn't the gold be separated from the stainless when the buffering material is dissolved into solution. Then give the stainless a vigorous shake and pluck it out.

 

[4metals]

If the Nitric boil will release the base/filler metal from the gold foils and also passivate the stainless, wouldn't the gold be separated from the stainless when the buffering material is dissolved into solution. Then give the stainless a vigorous shake and pluck it out.

This thread concerns reverse aqua regia. It contains both nitric and Hydrochloric Acids. What you are suggesting would be with straight nitric. (and some distilled water) You would use less acid and MAY dissolve out some base or filler metals but both the stainless and the gold will remain insoluble.

Worth a try.

 

[SinisterGenuis]

This thread concerns reverse aqua regia. It contains both nitric and Hydrochloric Acids. What you are suggesting would be with straight nitric. (and some distilled water) You would use less acid and MAY dissolve out some base or filler metals but both the stainless and the gold will remain insoluble.

Worth a try.

That is kinda what I am curious about, if both the gold and stainless are left what state are they left in? It be amazing if the foils just fell right off and manual seperation was as simple as plucking the stainless out.. But first chance I get I intend to find out.

 

[4metals]

Any gold that falls free will be either as an alloy because the nitric alone will not part anything over 10K alone, or as crumbled up gold which may get hung up in the stainless bands. Mechanically the gold may get broken into small bits, not for a single band but in larger lots for sure.

Let us know how you make out with this.

 

[Shark]

Picking 5 to 10 pounds of stainless bases from watchbands becomes a real pain pretty quick. I washed them through a food colander even if it did break up the foils somewhat, it was easier.

 

[SinisterGenuis]

Any gold that falls free will be either as an alloy because the nitric alone will not part anything over 10K alone, or as crumbled up gold which may get hung up in the stainless bands. Mechanically the gold may get broken into small bits, not for a single band but in larger lots for sure.

Let us know how you make out with this.

I read this and wanted to take some time to digest it before replying. So I was away on vacation and just got back last night and wanted to discuss further your point about "Nitric alone will not part anything over 10K". So when I seperate the Gold filled tops from the stainless band base and then refine, it would be the standard process that starts with a nitric boil to dissolve base metals from ther tops. These tops are all stamped as being usually 14K on average. But that is just a top layer and the nitric is dissolving away the base that it is bonded to. When i made mention to trying the whole band, I figured the Stainless base would be uneffected and the base metal that would be dissolved would be the same as if you manually seperated them. Which in my thinking is what is mainly holding it to the Stainless bottom. But at this point just a Hypothesis mixed in with a little hope. I just got done sorting some bands I deemed expendable and will set out over the next few days for trial n error. After scratching it out on paper my calculations show i would not be happy with the amount of nitric used in RaR.

 

[4metals]

After scratching it out on paper my calculations show i would not be happy with the amount of nitric used in RaR.

True, reverse aqua regia is more useful for commercial refiners than for hobby refiners that can be "nitric challenged."