Ag in AR

[mosfetta]

Hello everyone.
advice, I have melted material containing silver and gold in AR.
I precipitate with sulphamic acid and metabisulphite.
the precipitate is a mixture of silver and gold chloride.
question: what is the best method to divide and select the precipitate?

 

[4metals]

What was the percentage of silver to start with?

 

[mosfetta]

What was the percentage of silver to start with?

30%

 

[4metals]

I assume at 30% Silver you have a lot of white encrusted chunks that did not dissolve?

 

[mosfetta]

30%

.

I assume at 30% Silver you have a lot of white encrusted chunks that did not dissolve?

I'm doing some tests.
for the moment I'm not interested in quantity or anything else but in the method of dividing in a qualitative way. Thank you

 

[FrugalRefiner]

After you've dissolved all that will dissolve in AR, you should add ice to the solution to chill it and dilute it. That will cause almost all silver chloride (AgCl) to precipitate and join the undissolved material. If there is any possibility of lead in what you've dissolved, add a bit of sulfuric acid to precipitate it as well.

Then filter the solution till it is absolutely clear. That will separate the silver from the gold.

Then precipitate the gold from the solution using the precipitant of your choice.

Dave

 

[4metals]

30% Silver is too much Silver in the alloy for it to effectively dissolve. The most effective separation will be to inquart the alloy with silver so the gold concentration is 25% of the alloy. (In other words add silver and re-melt it into shot). The inquarted gold will now be separated by putting the alloy into nitric acid. The silver will dissolve out leaving you gold which can approach 99% by parting in nitric. Then if you want more purity the gold is dissolver in aqua regia and refined normally. The silver is recovered by cementation on copper.

This is an over simplification of a process we have covered on the forum many times.

If you need clarification let us know and we will post links to threads to detail the process.

 

[Yggdrasil]

.

I'm doing some tests.
for the moment I'm not interested in quantity or anything else but in the method of dividing in a qualitative way. Thank you

You need to study more.
When ever there is Chlorides present, Silver will not dissolve, it just forms Silver Chloride.
So if it is over 7.5% Silver or around there, the Silver Chloride formed will protect the Gold and nothing much will dissolve.

 

[mosfetta]

30% Silver is too much Silver in the alloy for it to effectively dissolve. The most effective separation will be to inquart the alloy with silver so the gold concentration is 25% of the alloy. (In other words add silver and re-melt it into shot). The inquarted gold will now be separated by putting the alloy into nitric acid. The silver will dissolve out leaving you gold which can approach 99% by parting in nitric. Then if you want more purity the gold is dissolver in aqua regia and refined normally. The silver is recovered by cementation on copper.

This is an over simplification of a process we have covered on the forum many times.

If you need clarification let us know and we will post links to threads to detail the process.

as usual you are perfect and very helpful. I thank you.

 

[mosfetta]

You need to study more.
When ever there is Chlorides present, Silver will not dissolve, it just forms Silver Chloride.
So if it is over 7.5% Silver or around there, the Silver Chloride formed will protect the Gold and nothing much will dissolve.

Greetings.
I'm an electronics engineer, I have difficulty thinking like a chemist, I would be grateful if you bear with me in my questions. Thank you

 

[Yggdrasil]

Greetings.
I'm an electronics engineer, I have difficulty thinking like a chemist, I would be grateful if you bear with me in my questions. Thank you

Have you studied the links I gave you?

 

[4metals]

I'm an electronics engineer

If you are en electronics engineer is the material you are working with electronics waste or is it karat gold alloy or some other alloy in bar form? The method suggested, inquartation is not the answer for all scraptypes. If you are more specific we can be more specific.

 

[mosfetta]

If you are en electronics engineer is the material you are working with electronics waste or is it karat gold alloy or some other alloy in bar form? The method suggested, inquartation is not the answer for all scraptypes. If you are more specific we can be more specific.

Well!!!!
I may have many cell phones to work on, many computer motherboards and equipment boards.
I'm studying a better way to work with this materialb
I would be grateful if you would help me. Thank you

 

[mosfetta]

in this period I'm trying to work on mobile phone PCBs directly on AR and separate the various metals.

 

[4metals]

That material is not material for inquarting. My work on e-scrap involved much larger scale smelting processes which, while useful, are often too equipment intensive for a startup.

Many members here process this type of material with solvent chemistry vs pyro-metallurgy and they will be better served to share with you.

 

[mosfetta]

After you've dissolved all that will dissolve in AR, you should add ice to the solution to chill it and dilute it. That will cause almost all silver chloride (AgCl) to precipitate and join the undissolved material. If there is any possibility of lead in what you've dissolved, add a bit of sulfuric acid to precipitate it as well.

Then filter the solution till it is absolutely clear. That will separate the silver from the gold.

Then precipitate the gold from the solution using the precipitant of your choice.

Dave

Thanks Dave.
I'm interested in your answer.
The AR solution I have to work with comes from mobile phone PCBs immersed in AR by removing only the iron parts.
Is the method still good?

 

[Yggdrasil]

Thanks Dave.
I'm interested in your answer.
The AR solution I have to work with comes from mobile phone PCBs immersed in AR by removing only the iron parts.
Is the method still good?

It is never a good idea to dissolve Gold on PCBs, the dissolved Gold can cement out on the PCB traces and that can be inside the fiberglass matrix.
The way it is best done is to dissolve the Copper under the Gold layer and such free the plated Gold and collect it.
Usually the Gold on these has very thin plating (ENIG).

There are literally thousands of posts discussing this on this forum.
Search for it.

 

[GoIdman]

Thanks Dave.
I'm interested in your answer.
The AR solution I have to work with comes from mobile phone PCBs immersed in AR by removing only the iron parts.
Is the method still good?

hi, no its not good, especially with mobile phone boards.

Older phone PCB contain a lot of lead in solder, newer ones with ROHS compliance contain lots of tin.

You need to separate everything from the PCB sort and work with every material separately

You need a very large amount of PCB to recover meaningful quantity of PM and it is very labour intensive .

You have to get rid of solder in order to work yourself to recover the PM`s otherwise you will end up with a large mess with every junk in your solution.

Solder can be removed with HCl bath.

Pete

 

[anachronism]

hi, no its not good, especially with mobile phone boards.

Older phone PCB contain a lot of lead in solder, newer ones with ROHS compliance contain lots of tin.

You need to separate everything from the PCB sort and work with every material separately

You need a very large amount of PCB to recover meaningful quantity of PM and it is very labour intensive .

You have to get rid of solder in order to work yourself to recover the PM`s otherwise you will end up with a large mess with every junk in your solution.

Solder can be removed with HCl bath.

Pete

Pete's pretty much summed it up here Mosfetta. Pick your battles otherwise it all comes unglued very quickly with huge amounts of pointless waste.

 

[anachronism]

It is never a good idea to dissolve Gold on PCBs, the dissolved Gold can cement out on the PCB traces and that can be inside the fiberglass matrix.
The way it is best den is to dissolve the Copper under the Gold layer and such free the plated Gold and collect it.
Usually the Gold on these has very thin plating (ENIG).

There are literally thousands of posts discussing this on this forum.
Search for it.

As advice for a basic recovery system this is sound, however using the correct mix of AR solution there is no re-deposition at all. Also, the losses would be minimal if any at all if done correctly.