Expert: Henry Boyter - 1/31/2002

Question
Hello.  My soon-to-be five year old has stumped me...hoping you can help.  If you take metals and melt them together to make an alloy - is it possible to get the original metals back some how? For instance pewter which is (I believe) primarily tin with some antimony and copper.  After you've made your pewter lamp - can you later get back the copper, tin and antimony?  Or are they irretrievably now intertwined?  How about bronze - which I believe is a copper-zinc alloy?  

Answer
The way to do it is to first dissolve the metal object in strong acid (very dangerous unless trained).  This converts the metals to their salts (Zn to Zn+2 for example).  The salts are easily separated from each other by chemical reactions.  Then you covert the salts back to metals by electrolysis for example.  You can also probably do it in most cases by melting the metals.  Each separate metal would have a different density and separate (like oil and vinegar), but this would be hard to do in practice (very high temperatures)