Thanks fellas. I have an old elementary arithmetic book I think I should post on here. I know at least one person who could really use it.
I'm not sure what your post means, or who it directed at, but my math is correct.
And no magic here-just something called borax. It lowers the melting temperature of the silver AND removes impurities so they never even make it into the mold!
Also, there's something called math that comes into play. I'll simplify things for you. Say you have .9 grams of 90% silver. So, to make it more pure you add .1+ grams of silver shot (basically pure silver).
You can't simply add 0.1 oz. of pure silver to 0.9 oz of 90% silver to get 1 oz. of 99% silver because your silver still has 0.09 oz. of impurities. Adding 0.1 oz of pure silver to 0.9 oz. of 90% silver gives you 1 oz. of 91% silver. Like I wrote before, you have to add 6.5 oz of pure silver to 1 oz. of 92.5% silver in order to dilute the impurities enough to get 99% silver.
Anyway, I always wondered how refining works.
I don't know much about it but the information online only talks about using nitric acid to refine silver. It doesn't say anything about using borax to refine silver, only for use as a flux. How well does it work? You should end up with a pretty good chunk of alloy when you go from 92.5% to 99%.