How Aluminium Foil is made?
Aluminium is the most abundant metal in the earth’s crust. Actually, it makes up between 7 and 8 percent of the crust. But aluminium is never found in a pure state in nature. Rather, it is combined with other chemical elements in compounds that are very hard to break down. The most important ore of aluminium is bauxite, a type of clay. This generally contains from 40 to 60 percent aluminum oxide.
Aluminium has a number of properties that make is useful for many products. Aluminium is light, weighing one third as much as such metals as iron, copper, nickel, or zinc. Aluminium conducts electricity well and is also a good heat insulator, because its shiny surface reflects away heat rays. And aluminium resists corrosion; when it is exposed to air, aluminium immediately combines with some of the oxygen to form a thin, tough, colorless film that protects the metal against further chemical action, thus preventing rust.
For these and other reasons, aluminium is used in making foil. Foil is any metal sheet that measures 0.005 of an inch or less. To roll a metal this thin machines of great precision are needed. Even the smallest change in measurement shows up in foil. Different kinds of mills have been developed to roll out aluminium and other metals to the exact thickness desired.
Aluminium is so malleable that it can be rolled into sheets of foil as thin as 0.0002 of an inch. In such cases, pure aluminium is used. For most other things, and for greater strength in the foil, aluminium alloys are used. In these instances other metals are combined with aluminium.
The aluminium foil you use at home resists moisture and gas, is greaseproof, odorless, and tasteless, resists corrosion, reflects away heat and shuts out light.
Writer: Ahmed Matiur Rahman