Aluminium is the most common element after oxygen and silicon on the earth’s crust, comprising 8% of the crust. No other metal is available in such quantities, and its many advantageous characteristics make it a very adaptable light metal.
Targeted adaptations using alloying engineering produce optimal properties in the material: aluminium is easy to process, offers great freedom in design, with a long lifetime and good resistance to weathering. These outstanding characteristics are further enhanced through a suitable surface treatment. Anodic oxidation satisfies the widest variety of demands on the material.
Some of the key advantages of aluminium are:
Aluminium products can be melted down any number of times, with the recovered aluminium remaining of a consistently good quality.
http://en.wikipedia.org/wiki/Aluminium