# 27% Tin with 68% Silver



## metatp (Aug 21, 2009)

Well I still haven't graduated to gold yet. I am still messing with different silver I have. My issue this time is around Silver that has about 27% Tin. I have these small pellets (about .4g each). I try soaking a few of them in 30% Muriatic acid for over 24 hour. It removed some of the tin, but based on the weight, less them 1/4 of it. I then tried to crush the pellet into even smaller pieces and soak again. That worked much better. I thought most of the tin was dissolved. After rinsing in DI water, I place about 10g in nitric acid 50/50 with DI water. The reaction was fast, but it was obvious that tin was still present. I had a hard time even filtering this 10g batch. After a long time in filtering and lots of DI water (400ml or so) I felt I got as much silver nitrate as reasonable.

Here is my questions:
1. Is there a better way to remove the tin?

2. The solution was slightly clouding instead of the clear silver nitrate that I am used to. If i drop the silver with copper, will the silver be contaminated with tin after filtering the cement? The silver appeared to cement out very easily, and the solution was a nice clear blue. it also appears that the product does match the 68% silver. When I filter the cemented silver, the rinse was slightly cloudy.

3. What purity should I expect, and should I rinse the silver powder in diluted Muriatic acid for a few minutes before I melt?

4. Does copper dissolve in Muriatic acid? the pellets are supposed to have 5% copper, but the solution in nitric was only very slightly bluish green.

I look forward to any advice or opinions that anybody might have. I have about 12 oz to play with.

Thanks,
Tom


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## Harold_V (Aug 22, 2009)

HTPatch said:


> Here is my questions:
> 1. Is there a better way to remove the tin?


Yep!
Incineration, then a nitric digest. 

I used to process dental amalgam that way (after retorting). The percentage of tin present lowers the melting point considerably, so if you incinerate hot enough, the metal will melt. It should then be stirred (you can use a steel rod, maybe 3/8" diameter. Heat the material in an old stainless frying pan), exposing the alloy to oxygen (atmosphere appeared to be enough). Keep stirring when the material is removed from heat, and you end up with rather strangle looking metal bits that are readily attacked by nitric, and yield a solution that readily settles, so you need filter only the last small amount, to wring the values form the tin. The solution should filter fairly well once the material has been well oxidized. 

The silver recovered with copper will most likely be in the neighborhood of 99% pure. If you want pure, it is best parted in a silver cell. 

Harold


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## goldsilverpro (Aug 22, 2009)

Ag/Sn can be run through a silver cell. The tin forms metastannic acid, a solid, which stays on top of the filter cloth.


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## metatp (Aug 22, 2009)

Incineration. I will give that a try. The pellets I have are actually used for dental amalgam back in the late 70s. 99% purity is fine, but it appear that I may want to make one of those silver cells some day.

You guys are great!!! 

One other non-related question. If I wanted to try my hand at refining gold, what it the best source to start with? I am mainly interested in learning, so if I break even in cost/recovery, that would be a plus. Should I try some escrap (finger?) or scrap karat gold jewlery? I read a lot about refining gold on this forum, but don't really have any scrap to refine yet.

Thanks again. Some day I hope to repay the favor with more than just a word of thanks.

Tom


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