# Best way to remove contaminates?



## rickbb (Nov 20, 2013)

OK, so against the excellent advice of the good people here, I processed about 100lbs of old x-ray film. I know I should have just sold the film but I wanted to learn and I’m a little hard headed that way. (OK I’m a lot hard headed but that’s a different discussion.)

I used the traditional method, stripped the films in heated NAOH and then incinerated the sludge. I now have about 12 ½ ozt of powder. But there appears to be something other than silver in it.

I used an old stainless steel pot to incinerate in, let it go until it quit smoking and got the powder a dull red. Stirred it up to make sure it was all nice and hot, left it for 20 30 minutes like that.

After it all cooled down I started looking at it and there is red flaky parts in it. And there were the same flakes as a crusty ring around the pot at the top of where the powder line was. 

Is this some iron scale from the stainless pot or was this something in the sludge?

More importantly what would be the best way to proceed to get some clean silver? If I dissolve with weak nitric and cement with copper won’t that also cement the base metal, if that is what this is?


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## Lou (Nov 20, 2013)

Best just to melt it with carbonate and borax as per goldsilverpro's suggestion.

Iron won't contaminate the silver (the other elements in the stainless, certainly).


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