# Redissolve my silver powder



## Rreyes097 (Sep 17, 2022)

Does anyone have any tips on how to dissolve silver powder for greater purity?


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## FrugalRefiner (Sep 17, 2022)

Silver cell?

The question is vague, and so is my answer.

What is the source of your silver powder? What result are you trying to achieve? For what purpose?

Dave


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## Rreyes097 (Sep 17, 2022)

My apologies. I had a bunch of silver powder I have got from various silver. I was going to melt that silver but I wanted to reliquify it and cement it out with copper just to try to purify it even more but I don't have a silver cell so this is the route I was going. So far it's not going well.


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## sirex (Sep 17, 2022)

Total noob here. Someone will correct me if I'm wrong.

I'd assume you would dissolve with nitric to get silver nitrate and then cement it out with your copper. Making sure to rinse the powder really well with hot water multiple times until it runs clear and then wash with hot hcl.


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## Rreyes097 (Sep 17, 2022)

That's what I'm trying to do. I've made silver nitrate and chloride. Worked with silver quite a bit. But I never tried to do a large batch of silver nitrate. But I've had it on a hot plate all day and nothing! Maybe too much silver?


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## 4metals (Sep 17, 2022)

Rreyes097 said:


> I've made silver nitrate and chloride.


Did you use tap water with your nitric? If you used distilled you should be chloride free. 

Why don’t you search for the caustic and sugar method here and use that? It can yield very high purity Silver with good rinsing.


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## Rreyes097 (Sep 18, 2022)

No I used distilled water. But I was just saying I've used both ways to get silver.


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## orvi (Sep 18, 2022)

Rreyes097 said:


> My apologies. I had a bunch of silver powder I have got from various silver. I was going to melt that silver but I wanted to reliquify it and cement it out with copper just to try to purify it even more but I don't have a silver cell so this is the route I was going. So far it's not going well.


Present your aimed purity and methods of how you obtained silver powder. We cannot help you much if we do not know what you have and what you want from it.

If you filter the dissolved solution of silver and base metals nicely clear, dilute it so no oxidation of copper to shedding copper oxides happen, you can get around 98-99% Ag by means of copper cementation. Rest would be copper which flakes off with it.

If you redissolve silver in nitric and proceed with AgCl drop, thorough washing with hot water and then lye/sugar conversion, you can reliably get 99,9% Ag. 

If you take ca 92-93+% silver and run it through the silver cell, you also obtain 99,9% Ag if done right. Higher starting Ag is, better purity and less problems you will have with it.

Additionally, you can reduce silver nitrate solution with formate to also obtain 99+% Ag, but in larger scale this is rather tedious in my opinion, and lye/sugar is easier to perform.

Make simple silver cell from a stainless bowl, DC power supply you can easily make from old PC ATX power supply - it has 3,3V out at high amps, you add some variating resistor or wire from some heating spiral to adjust the current/voltage and you are running  Altough much more convenient is buy small DC/DC step-down converter module with constant current feature. On Aliexpress, you can get them for like 5euros.

But if it is one time thing and you won´t have enough raw silver to feed the cell in the future, go with lye/sugar.


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## Rreyes097 (Sep 18, 2022)

I was simply hoping for the best purity I could produce with the simple means i possess. I have already put it in distilled water and nitric acid and not much has happened. Little but of red smoke of nitric acid. But it looks as if all the silver remains undissolved. I guess I'll just rinse it really well and call it good!


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## 4metals (Sep 18, 2022)

Rreyes097 said:


> I have already put it in distilled water and nitric acid and not much has happened.


Is it really silver? If it is, it would have dissolved in the nitric solution. How much metal was added to the reaction, and how much Silver? What was the starting material? 

From what you have said so far it may be silver plated stainless steel and all of the Silver is already in the acid. 

Being vague here really will not help you much.


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## mythen10 (Sep 18, 2022)

Rreyes097 said:


> Does anyone have any tips on how to dissolve silver powder for greater purity?


why is so hard?
1.disolve the powder in dilute nitric 
2.if you wanna get pure 99,9 silver don't cement with copperi n this way you wil get 98-99% silver and is not pure 
3. add HCl acid to the filtrated nitric batch the silver will precipitate instantly and let 1 hour to cool down on the bottom and after wash the silver chloride several times with hot water 
4.add sodium hydroxide to silver chloride to convert in silver oxide 
5. add shugar to silver oxide and you will get you pure 99,9 % silver


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## orvi (Sep 18, 2022)

Rreyes097 said:


> I was simply hoping for the best purity I could produce with the simple means i possess. I have already put it in distilled water and nitric acid and not much has happened. Little but of red smoke of nitric acid. But it looks as if all the silver remains undissolved. I guess I'll just rinse it really well and call it good!


Did you heated the solution ? Silver often need some heating to get reasonable reaction ongoing. But be very careful as finely divided metal can spiral out in exponential way with runaway reaction. For digesting powders, always use much bigger vessels than you need and proceed with slow addition of nitric to avoid sudden furious reaction to foam out of the beaker.

If it is heated and still does not react, it probably isn´t silver.


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## 4metals (Sep 18, 2022)

One rule I always follow is when in doubt, do a small part of the lot in a beaker just to work out the chemical usage and see what you can expect. 

In a refinery I like my surprises to be small. I guess that makes me a boring guy.


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## mythen10 (Sep 18, 2022)

if is not dissolve in nitric is possible to be Wolfram , right now I have more than 2 kg silver contacts from electrial switches and when I dissolve in nitric only around 80% is go in solution and 20% remain in a dark grey powder wich is Wolfram , the contacts are silver Wolfram alloy 80-20%


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## Rreyes097 (Sep 18, 2022)

Thank you for everybody's replies. So it looked like it all actually eventually went into the nitric. The silver came from various silver things coins jewelry lots but I dissolved it into silver nitrate powder and then tried to redissolve it. But I have cemented it all out and it is back to being silver nitrate. I guess that's going to be the best purity I can do with the tools at hand. And yes I did warm it up. It was just a lot of silver and it took a lot of nitric and it took a lot of time.

Someone mentioned that after all the dissolved silver there is some gray matter at the bottom this I have. Is it not silver then?


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## orvi (Sep 19, 2022)

Rreyes097 said:


> Thank you for everybody's replies. So it looked like it all actually eventually went into the nitric. The silver came from various silver things coins jewelry lots but I dissolved it into silver nitrate powder and then tried to redissolve it. But I have cemented it all out and it is back to being silver nitrate. I guess that's going to be the best purity I can do with the tools at hand. And yes I did warm it up. It was just a lot of silver and it took a lot of nitric and it took a lot of time.
> 
> Someone mentioned that after all the dissolved silver there is some gray matter at the bottom this I have. Is it not silver then?


Again, if it does not dissolve in nitric, it isn´t silver. Decant, add bit of fresh nitric and observe reaction in closed beaker while heating. If no NOx fumes evolve, there is no silver.


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## mythen10 (Sep 19, 2022)

Rreyes097 said:


> Thank you for everybody's replies. So it looked like it all actually eventually went into the nitric. The silver came from various silver things coins jewelry lots but I dissolved it into silver nitrate powder and then tried to redissolve it. But I have cemented it all out and it is back to being silver nitrate. I guess that's going to be the best purity I can do with the tools at hand. And yes I did warm it up. It was just a lot of silver and it took a lot of nitric and it took a lot of time.
> 
> Someone mentioned that after all the dissolved silver there is some gray matter at the bottom this I have. Is it not silver then?


is Wolfram


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## mythen10 (Sep 19, 2022)

Rreyes097 said:


> Thank you for everybody's replies. So it looked like it all actually eventually went into the nitric. The silver came from various silver things coins jewelry lots but I dissolved it into silver nitrate powder and then tried to redissolve it. But I have cemented it all out and it is back to being silver nitrate. I guess that's going to be the best purity I can do with the tools at hand. And yes I did warm it up. It was just a lot of silver and it took a lot of nitric and it took a lot of time.
> 
> Someone mentioned that after all the dissolved silver there is some gray matter at the bottom this I have. Is it not silver then?


first time when I meet this problem I was believe that powder is PLATINUM but is Wolfram


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## BlackLabel (Sep 19, 2022)

How can I quickly and reliably distinguish between tungsten (wolfram) and platinum if it's in powder form?
I know, tungsten is nearly unmeltable.


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## orvi (Sep 19, 2022)

BlackLabel said:


> How can I quickly and reliably distinguish between tungsten (wolfram) and platinum if it's in powder form?
> I know, tungsten is nearly unmeltable.


Solid tungsten does not dissolve in nitric and coat itself with blackish oxide layer. In AR tungsten tend to be very slowly attacked and form yellowish-greenish coating on the metal - colour familiar to you if you ever dissolved CPUs or ceramic ICs in AR. That greenish-yellowish hue which stays on the places where traces or pins were is oxidized tungsten.
Platinum is slowly dissolved with AR and can be tested with stannous.

As we say in our shop, if it does not dissolve in nitric it starts to get interesting  and if it does not dissolve also in AR, high chances we toss it to waste bucket soon


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## BlackLabel (Sep 19, 2022)

Thanks Orvi.

I know, platinum shows a catalytic effect when covered with H2O2.
But it also could bubbling if there is other stuff in the beaker.


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## Rreyes097 (Sep 19, 2022)

Cool. I'll see. So what's it mean if it's Wolfram? Can it be sold? Is it tungsten? Is any of this gray matter worth selling or doing anything with?


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## Yggdrasil (Sep 19, 2022)

Rreyes097 said:


> Cool. I'll see. So what's it mean if it's Wolfram? Can it be sold? Is it tungsten? Is any of this gray matter worth selling or doing anything with?


Wolfram is Tungsten and what gives it the W name in the periodic table.


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## orvi (Sep 19, 2022)

Rreyes097 said:


> Cool. I'll see. So what's it mean if it's Wolfram? Can it be sold? Is it tungsten? Is any of this gray matter worth selling or doing anything with?


Tungsten can be sold to some buyers, but I am afraid only in some decent few kg quantity.


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