Is there any simple way to separate aluminum from plastic?
A number of simple methods to separate aluminum and plastic can be devised. These depend on the differences in the properties of these two materials. We can use differences in the density and melting points to our advantage.
Differences in density: aluminum has a specific gravity (ratio of density of a substance to that of a standard fluid, typically water) of 2.7. In comparison, depending on the plastic in question, the specific gravity may vary from 0.6 to about 2.3. Thus, plastic is lighter than aluminum and we can use this to separate them. We can suspend the aluminum-plastic mixture in water and mix it thoroughly and allow it to settle, and obtain different layers of plastic and aluminum.
Differences in melting point: Aluminum has a melting point of 660 degrees Celsius, while that of different types of plastics vary between 100-250 degrees Celsius. Thus, we can melt a mixture containing plastics and aluminum to say up to 300 degrees C and remove all the molten plastic, leaving behind aluminum.
Hope this helps.