Refining old silverware

[Sunnyket]

You do not want Aqua Regia and Tin in the same beaker together.
Nitric and Tin creates Metastannic acid, which is a nightmare to filter

Thanks for the correction sir,
I remember one of my gold recovery process struggled to filter it took me 3-4 days to filter clearer solution.
Please explain following
In aqua regia process the filtered solution looks very much dark ! This happened first time. (Currently- Process of filtering is still going on I'll update later )

 

[Yggdrasil]

Thanks for the correction sir,
I remember one of my gold recovery process struggled to filter it took me 3-4 days to filter clearer solution.
Please explain following
In aqua regia process the filtered solution looks very much dark ! This happened first time. (Currently- Process of filtering is still going on I'll update later )

If you don't provide more detail it is impossible to answer.

 

[Sunnyket]

Yes sir,
In first' i refined silver with nitric then i got residue contains gold, tin, nickel, tungsten, lead, osmium, iridium, ruthenium, iron (and other metals too in less percentage i.e. half percentage so not mentioned) in brown powder type form.
so i followed aqua regia process to obtain gold
what actually i did AR step by step as follows #
1. 280GM of powder i took 300 ml nitric and 900ml HCL and placed on flame.
2. Above quantity of AR solution added in two batches.
3. After 45 minutes i thought AR is needed so added 70ml nitric and 210 ml HCL
4. flames turned off after Approximately 2hours because brown fumes not stopped so i waited that much long.
5. Boiling flask Kept aside for cooling 2 hours
6. Added 30-40 ml sulphuric acid to settle down base metal
5 after one and half hour took solution in beaker and added industrial grade UREA to neutralize process.
6. And started filtration process.
7.but the filtered solution colour looks darkest yellow type.
I'm confused here what happened with solution. Please guide me in this. Currently i started filtering again that solution
Thanku

 

[Yggdrasil]

Yes sir,
In first' i refined silver with nitric then i got residue contains gold, tin, nickel, tungsten, lead, osmium, iridium, ruthenium, iron (and other metals too in less percentage i.e. half percentage so not mentioned) in brown powder type form.
so i followed aqua regia process to obtain gold
what actually i did AR step by step as follows #
1. 280GM of powder i took 300 ml nitric and 900ml HCL and placed on flame.You never mix AR in a fixed ratio, add HCl and then Nitric in increments
2. Above quantity of AR solution added in two batches.
3. After 45 minutes i thought AR is needed so added 70ml nitric and 210 ml HCL
You already had in AR right? And you had enough AR to dissolve several hundred grams of Gold.
4. flames turned off after Approximately 2hours because brown fumes not stopped so i waited that much long. The Brown fumes tell that it is not done.
5. Boiling flask Kept aside for cooling 2 hours
6. Added 30-40 ml sulphuric acid to settle down base metal Sulfuric is used to drop Lead only not base metals in general.
5 after one and half hour took solution in beaker and added industrial grade UREA to neutralize process.
We do NOT use Urea here, we use Sulfamic acid which has a much better function in addidtion to Sulfuric as the end product dropping the need for the previous step.
6. And started filtration process.
7.but the filtered solution colour looks darkest yellow type.
This solution probably still contains significant levels of NOx, Nitrates and excess Nitric. And unless you have pictures we have no way to assess the color.
I'm confused here what happened with solution. Please guide me in this. Currently i started filtering again that solution
Thanku

It seems you did not get a welcome
Welcome to us.

You really need to study more.
Comments in bold in the quote.
What kind of starting material did the powder come from?
How do you know the content of your powders?

I have a task for you and until that has been done I suggest you put away your solutions in a safe place and in containers with lids.

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: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library

 

[Yggdrasil]

Yes sir,
In first' i refined silver with nitric then i got residue contains gold, tin, nickel, tungsten, lead, osmium, iridium, ruthenium, iron (and other metals too in less percentage i.e. half percentage so not mentioned) in brown powder type form.
so i followed aqua regia process to obtain gold
what actually i did AR step by step as follows #
1. 280GM of powder i took 300 ml nitric and 900ml HCL and placed on flame.
2. Above quantity of AR solution added in two batches.
3. After 45 minutes i thought AR is needed so added 70ml nitric and 210 ml HCL
4. flames turned off after Approximately 2hours because brown fumes not stopped so i waited that much long.
5. Boiling flask Kept aside for cooling 2 hours
6. Added 30-40 ml sulphuric acid to settle down base metal
5 after one and half hour took solution in beaker and added industrial grade UREA to neutralize process.
6. And started filtration process.
7.but the filtered solution colour looks darkest yellow type.
I'm confused here what happened with solution. Please guide me in this. Currently i started filtering again that solution
Thanku

Ah, another thing did you do a stannous test?

 

[Sunnyket]

Ah, another thing did you do a stannous test?

Thanku sir,
Gold is tested by computerized machine. And gold is positive in solution.
I already downloaded hokes book through internet pdf copy.
In filtered solution i observed crystals are formed. I think gold sulphate is formed or additional urea salt is that I'm not sure.

 

[Yggdrasil]

Thanku sir,
Gold is tested by computerized machine. And gold is positive in solution.
I already downloaded hokes book through internet pdf copy.
In filtered solution i observed crystals are formed. I think gold sulphate is formed or additional urea salt is that I'm not sure.

Better use the link I gave you for Hokes.
It is slightly edited to remove some dangerous procedures.

Have you tested the solution for Gold?
Why do you assume Gold Sulphate?

And you have not answered what the starting material was and why you think all those elements are in your material?

 

[Sunnyket]

Better use the link I gave you for Hokes.
It is slightly edited to remove some dangerous procedures.

Have you tested the solution for Gold?
Why do you assume Gold Sulphate?

And you have not answered what the starting material was and why you think all those elements are in your material?

As above i mentioned, i refined raw silver in nitric i obtained pure silver (as well obtained copper -with iron process)
After silver refining filtered powder obtained on filter paper,
that powder is after tested in metal testing machine,
Machine shows various metals including gold.

Gold sulphate I'm assuming because it is in crystal form.
..
I'm going to read hokes book surely
But i need to clean all the stuff now. Bcz i need money so please advise what to do on this current scenario
Thanku sir

 

[Yggdrasil]

As above i mentioned, i refined raw silver in nitric i obtained pure silver (as well obtained copper -with iron process)
After silver refining filtered powder obtained on filter paper,
that powder is after tested in metal testing machine,
Machine shows various metals including gold.

Gold sulphate I'm assuming because it is in crystal form.
..
I'm going to read hokes book surely
But i need to clean all the stuff now. Bcz i need money so please advise what to do on this current scenario
Thanku sir

You are so vague it is hard to know what has actually been done.
Raw Silver means Ore or Dore?
The left over powder is just from the Nitric parting?
The test has been done in what kind of machine?
XRF, ICP-MS or what?
Gold Sulphate don't form easily as far as I know.
Most likely Excess Urea.
Why did you use Urea in the first place,Youtube?
Next why did you post in this section, it do not belong here since thread is discussing a specific alloy.
I will move it as soon as you can give a more precise description of the starting material, dore, ore or something else.

 

[Sunnyket]

You are so vague it is hard to know what has actually been done.
Raw Silver means Ore or Dore?
The left over powder is just from the Nitric parting?
The test has been done in what kind of machine?
XRF, ICP-MS or what?
Gold Sulphate don't form easily as far as I know.
Most likely Excess Urea.
Why did you use Urea in the first place,Youtube?
Next why did you post in this section, it do not belong here since thread is discussing a specific alloy.
I will move it as soon as you can give a more precise description of the starting material, dore, ore or something else.

I'm really sorry for this.. I'm not good at English. language barrier to tell the all details.
I don't understand dore and ore
Raw silver means old ornaments, silver jewellery with gold plated, mostly ornaments of silver are alloyed with copper, when old jewelry is melted it is what we call here "raw silver" it is like 75% silver 23% copper 2 % other mixed metals mostly zinc, cadmium, nickel, lead and mainly in small amount of gold. After many lots of silver refining we get mixed metal on filter paper.


So i received old jewelry silver in melted form and i refined that using nitric and precipitated using copper. In this process i obtained pure silver and other main is copper.

Where i tested is machine details--

Small spot energy dispersive X-ray fluorescence (ED-XRF) spectrometer optimized for precious metal testing and compliance screening​

Yes sir, you're right about excess UREA.

Yes sir, unfortunately I followed youtube.

Actually i did Aqua regia process 5-6 times i struggled with tin in gold. So i Searched about this and this thread comes so i posted it here.

 

[Yggdrasil]

I'm really sorry for this.. I'm not good at English. language barrier to tell the all details.
I don't understand dore and ore
Raw silver means old ornaments, silver jewellery with gold plated, mostly ornaments of silver are alloyed with copper, when old jewelry is melted it is what we call here "raw silver" it is like 75% silver 23% copper 2 % other mixed metals mostly zinc, cadmium, nickel, lead and mainly in small amount of gold. After many lots of silver refining we get mixed metal on filter paper.


So i received old jewelry silver in melted form and i refined that using nitric and precipitated using copper. In this process i obtained pure silver and other main is copper.

Where i tested is machine details--

Small spot energy dispersive X-ray fluorescence (ED-XRF) spectrometer optimized for precious metal testing and compliance screening​

Yes sir, you're right about excess UREA.

Yes sir, unfortunately I followed youtube.

Actually i did Aqua regia process 5-6 times i struggled with tin in gold. So i Searched about this and this thread comes so i posted it here.

How is the sample when tested, in powder form or smelted bead?
Ore is the minerals which contain the metals when mining.
Dore, is the raw bars the mining industry make.
If it is really old silver it may contain some Pd, but that will follow the Silver into the Nitric.

I recommend you to make some Stannous Chloride solution, then you will have the opportunity to test the solutions directly and when refining.
This XRF is it yours, or something you can go to for testing?
XRFs are notoriously skecthy when testing powders and ores, if they pick up a spike it checks its library and find the closes match.
It can be used for powders and even liquids, but then the sample have to be prepared after very specific protocols.
Stannous on the other hand works for all the most common PMs, excluding Silver, Iridium and Rhodium.
Not that Iridum and Rhodium are common.

And drop the youtube, it is down right dangerous if you are not lucky enough to find a good poster, like Sreetips, Owltech and a few others.
Maybe 90% or more, of our "help me" posts come from youtube students.
Most youtube videos are made for the clicks and likes to make money and do not care if their procedures work or not,
they just edit it to look good.

 

[Yggdrasil]

As above i mentioned, i refined raw silver in nitric i obtained pure silver (as well obtained copper -with iron process)
After silver refining filtered powder obtained on filter paper,
that powder is after tested in metal testing machine,
Machine shows various metals including gold.

Gold sulphate I'm assuming because it is in crystal form.
..
I'm going to read hokes book surely
But i need to clean all the stuff now. Bcz i need money so please advise what to do on this current scenario
Thanku sir

Describe this part a bit more specific.
You dissolved all in Nitric, then filtered or then cemented on Copper?

 

[Yggdrasil]

I moved your thread here.

 

[Sunnyket]

Describe this part a bit more specific.
You dissolved all in Nitric, then filtered or then cemented on Copper?

Silver refining
As you say dore it contains approx. 75%silver 23% copper 2 % mixed metal. ratio It can vary with different batches
(Old jewelry melted) silver bar placed in reactor with nitric acid.
After 3-4 hours copper and silver turns into liquid state.
Then we filter it through( filter nylon cloth)this is type of filter paper we can use many times.
In filtring process solid dust(mixed metal) particles stay on filter.
Next stage is silver dust obtaining (using copper)
For precipitation we use (solid) copper powder.

From the above liquid we get silver dust and remains water contains copper.
Later, We process by adding iron in that remaining water and obtain copper.

 

[Sunnyket]

How is the sample when tested, in powder form or smelted bead?
Ore is the minerals which contain the metals when mining.
Dore, is the raw bars the mining industry make.
If it is really old silver it may contain some Pd, but that will follow the Silver into the Nitric.

I recommend you to make some Stannous Chloride solution, then you will have the opportunity to test the solutions directly and when refining.
This XRF is it yours, or something you can go to for testing?
XRFs are notoriously skecthy when testing powders and ores, if they pick up a spike it checks its library and find the closes match.
It can be used for powders and even liquids, but then the sample have to be prepared after very specific protocols.
Stannous on the other hand works for all the most common PMs, excluding Silver, Iridium and Rhodium.
Not that Iridum and Rhodium are common.

And drop the youtube, it is down right dangerous if you are not lucky enough to find a good poster, like Sreetips, Owltech and a few others.
Maybe 90% or more, of our "help me" posts come from youtube students.
Most youtube videos are made for the clicks and likes to make money and do not care if their procedures work or not,
they just edit it to look good.

Actually after nitric process the filtered solution we get is in browny in colour powdered form.

XRF is available in my locality. I ran a business of silver refining. Nearby of our shop XRF machines are available to test metal

Okey I'll do stannous chloride test.

Yes absolutely.. I'm feeling same about youtube

 

[Yggdrasil]

Actually after nitric process the filtered solution we get is in browny in colour powdered form.

XRF is available in my locality. I ran a business of silver refining. Nearby of our shop XRF machines are available to test metal

Okey I'll do stannous chloride test.

Yes absolutely.. I'm feeling same about youtube

Then it became clearer.
If you are going to test the sludge with XRF I recommend to melt it to a bead and hammer it flat before XRF, if it is possible.
XRFs will be more accurate then.
How much sludge do you generate monthly?
All the PGMs showing up seems unlikely and probably are a fluke of the XRF.
If you can, get some DMG, DiMethylGlyoxime to test for Pd in the Nitric.
What do you do with the Silver after separation?

Sreetips has some good videos on Silver if I remember correctly.
But he uses conversion to AgCl and from there to Ag if I'm not mistaken.

 

[Yggdrasil]

And change your habits regarding AR, add enough HCl to cover the material.
The weigh up the same amount of Nitric as your material,
in this case 280grams and add that to the heated HCl in batches of around 50ml-75ml at a time.
Every time the reaction dies down add another batch, if it stops before the Nitric has been used , add a bit more HCl.
And so on, until ALL is dissolved.
When dissolving Gold it is important that all base metals are completely dissolved.

Here is a good description on AR use: How much gold can ar dissolve ?

 

[Sunnyket]

Then it became clearer.
If you are going to test the sludge with XRF I recommend to melt it to a bead and hammer it flat before XRF, if it is possible.
XRFs will be more accurate then.
How much sludge do you generate monthly?
All the PGMs showing up seems unlikely and probably are a fluke of the XRF.
If you can, get some DMG, DiMethylGlyoxime to test for Pd in the Nitric.
What do you do with the Silver after separation?

Sreetips has some good videos on Silver if I remember correctly.
But he uses conversion to AgCl and from there to Ag if I'm not mistaken.

Next time I'll try sludge melting before AR process

 

[Yggdrasil]

Next time I'll try sludge melting before AR process

It will dissolve easier as a powder, what I meant was to take a pinch of the powder and melt for testing.
Knowing what is there may point to better ways to refine.

 

[Sunnyket]

And change your habits regarding AR, add enough HCl to cover the material.
The weigh up the same amount of Nitric as your material,
in this case 280grams and add that to the heated HCl in batches of around 50ml-75ml at a time.
Every time the reaction dies down add another batch, if it stops before the Nitric has been used , add a bit more HCl.
And so on, until ALL is dissolved.
When dissolving Gold it is important that all base metals are completely dissolved.

Here is a good description on AR use: How much gold can ar dissolve ?

Thanks for details
I usually weight the sludge and same quantity 1 part Nitric and 3 parts HCL
Above ratio is okay for sludge?
I didn't understand..the concept of "if it stops before nitric has been used, add a bit more HCL."

Update on my AR process __
Filtered solution twice still solution colour deep dark yellow colour (looks nearly blackish)
Used distilled water to washout filter but salt formed instantly. They block filtration

After filtering solution added SMB into solution and another trouble is all the solution looks like creamy mud type.

So i added boiling water and it helped me to separate gold mud.(repeated 3-4 times)

I also tried one small batch( for trial purpose) with HCL bath. And after hot water bath to washout chemical.

Then dried mud in sand bath.

Before melting added little copper with gold dust to soften alloy
Also borax in crucible as well as in gold dust.

While melting some impurities came

Finally process completed after lots of barriers