Silver proscess with Nitric acid

[ron c]

I would like some help. I tried disolving a sterling silver container in nitric acid. I ended up with a tan and white sediment on the bottom of the container.
Could anyone tell me what that is?
Thanks
Ron C

 

[martyn111]

A picture would help in identifying the sediment which you refer to.
Have you diluted your nitric acid 50/50 with distilled water or used it neat from the container? what strength nitric were you using? what grade? or was it poormans nitric (homemade)?

 

[ron c]

No it was 70% nitric and I already dissposed of the material.
Could there been another metal present in that sterling container I dissolved?

 

[martyn111]

The sterling will be 7.5% non silver but the non silver content should dissolve in nitric.
You say you were using 70% nitric, if you didn't dilute it with distilled water it will not be as effective as diluted nitric.

 

[jimdoc]

No it was 70% nitric and I already dissposed of the material.

You shouldn't dispose of anything that you can't identify in this hobby. You may be sorry later.

Jim

 

[ron c]

I did dilute the nitric 75% with distiled water.
I chalked it up to a learning curve but do not want to make the same error again.
it was 8 ounces down the drain.

 

[Barren Realms 007]

That can get to be an expensive lesson to learn.

 

[ron c]

I have been succesful before, but the solution was green/blue. Then extracted the silver by replacing it with copper. This time it was tan and white sediment. I did not know where to go from there.

 

[martyn111]

I did not know where to go from there.

Here would have been preferable to disposing of the material.

 

[butcher]

Silver Items are sometimes filled with non metals, like epoxy fillers, (handles or bases), sometimes other metals like lead can be used for weight or other reasons, I do not know if this is what you had or not.

 

[ron c]

That could be a possibilty, that is what I asumed it was a contamination of some sort.
I will have to disassamble the piece next time.
Thanks

 

[nickvc]

From your description of your solution it sounds to me like you had a silver plated item, sterling silver is alloyed with copper which is what gives the solution that green blue colour but plated items are plated with fine silver which is basically colourless in solution and the powder could have been some of the metal in the alloy which nitric didn't dissolve.

 

[Harold_V]

That could be a possibilty, that is what I asumed it was a contamination of some sort.
I will have to disassamble the piece next time.
Thanks

Much of sterling (candlesticks, compotes, etc.,) is nothing but a thin skin, supported, inside, by a plaster or rosin form, as butcher so nicely described. In such a case, you would expect that there would be considerable contamination unless you dismantled the object to be processed. They are often marked as being filled, so check the embossing (on the base) prior to making any decisions. When all else fails, it does no harm to smack the item with a hammer. If it's filled, it generally will come apart. Should you find yourself in that position, eliminated all of the rosin or plaster, and look for steel stiffeners that are commonly used to strengthen thin sections. When all of the filler has been removed, along with any stiffeners you may find, it's a real good idea to incinerate the remains prior to dissolution. That's especially true if the filler was rosin, which tends to adhere to the silver. You can adequately incinerate the silver by simply hitting the material with a torch until it is quite hot. Do not melt, although even that would do no real harm.

Harold

 

[MysticColby]

What about nickel? when dissolved in nitric, is nickel soluble? I've heard it referred to that it isn't...
I've seen this same white powder myself. I always just incinerate and add it to the next batch, but it never seems to go away.

 

[watcher6880]

What about nickel? when dissolved in nitric, is nickel soluble?

Lazersteve has a chart in his PDF files on what metals are soluable in water, acid or part acid part water and what isn't. Just go to his site. A link in his signature will lead you there.

 

[Oz]

Nickel is soluble in nitric acid, it is also rather toxic in that state.

 

[MysticColby]

Tin Nitrate must of been what I was thinking of!