dental powder 67% silver 25%tin 6%copper 2%zinc

[Eamonn]

Hi
I have got hold of 16 ozs of dental powder containing
silver, 67% minimum; tin, 25% minimum; copper, 6% maximum; zinc, 2% maximum.
I want to seperate the silver before I melt it so I will get high purity silver.
Does anyone have ideas on the best way to do this?

 

[galenrog]

Not to be mean, but did you use the forum search tool (upper right, has the word "search" in a box)??

 

[goldsilverpro]

A silver cell will work. The metastannic acid formed by the tin stays on the filter.

 

[goldenchild]

Wondering if a boil in HCL first would work to get rid of the tin and zinc and some of the copper. But with the silver being finely divided would create much AgCl? If not you would then have to incinerate the silver and copper(if any remained) and then go to nitric.

 

[Eamonn]

Thanks for the replys. Much appreciated.

I have searched extensively on the subject.

Just wanted to make sure I havn't missed something simple.

Regards
Eamonn

 

[Eamonn]

This is what I might try first.
I might try Sodium Hydroxide which will ,I hope, react with the Tin to form soluble tin hydroxide. I'm not sure if it will react with Zinc and Copper. So much the better if it does.The Silver won't react with Sodium Hydroxide. I think it might react with Hydrochloric Acid which is why I don't want to try this while the Tin and Zinc are still there.

I can do this until the solution tests negative for tin.White precipitate with ammonium hydroxide.

I'll try this on a small sample as I'm not sure if it will work.