Brass is a solid solution of copper and zinc. Is there an easy way to take scrap brass metal, and separate it back into copper and zinc?
Arjuna34
Get it hot enough to boil away, and then condense the gas. Copper and zinc condense at different temps, so they will separate out.
That’s simple, but not necessarily easy. Just getting brass hot enought to boil may be difficult.
See Brass recycling
Brass is considerably more valuable recycled as brass than separated into its separate copper & zinc components.
Holy Mackerel. A distillery.
Apparently, you don’t need to vapourise the alloy, you can simply melt the Zinc out from the Copper, due to the great difference in melting terperatures…
Here’s a chart that lists melting points for several types of brass:
http://www.engineeringtoolbox.com/melting-temperature-metals-d_860.html
They are higher than the melting point or even the boiling point of zinc (1664 F). What happens if you heat brass up past the melting point of zinc, or even the boiling point? Why would a melting point for brass be listed if it’s no longer brass after that?
I think there’s one clue in the brass recycling link astro gave:
Does the zinc just sort of ooze out?
I think page 13 of this PDF (linked to from Tabby_Cat’s link) Lecture on Copper has the answer with their phase diagram, but it’s been about 18 years since my materials science class, so I’m not too sure what it reveals.
Arjuna34
IIRC, the problem with listing melting (or indeedm boiling) points of mixtures is that you get a whole range of temperatures.
Take for example, water. When ice is melting, the temperature is exactly zero. The temperature of the ice will remain at zero until all the ice has turned into water (ideally).
For a mixture, however, of say, milk, the milk “ice cube” will start melting at temperature x. But the temperature of the cube will continue rising while it melts, unlike water.
thats the funny thing about water and its phase changes though mainly because of its high specific heat when it melts that liquid pulls off all the heat that was generated to make it melt thus keeping it at 0 degrees celcius just like water never gets hotter than 212 degrees unless you heap on additional pressure against it
No. It fumes out. This is … not healthy for people. Catchy name, though.
I’ve worked with molten brass - a fume hood or doing it outdoors is a must.
No, that’s not a funny thing about water. That’s the way any pure substance behaves when going through a phase change.
Wow 2006 huh. I didn’t even remember that I said this. I’m still pretty sure I got it right though! 
No, the funny thing about water is that it melts at exactly 0 degrees C. I mean, what are the odds?
And, our new friend, while digging up zombies, mixes units as well. Getting water above 100 degrees (when you’re talking Celsius) is tough to do without a heap of additional pressure.
I must be dense this week … water melting at 4ºC would be hilarious …
It’s easy enough that nearly anyone learning to braze with an oxy-acetylene torch will do it a number of times before they get the knack.