Aluminum foil, sometimes simply referred to as tin foil, is a very versatile product. From keeping food items fresh for later use to spacecraft components, aluminum foil is widely used today for a variety of purposes. Have you ever wondered how this material is made?
Aluminum happens to be the most abundant metal found on Earth. It's also very durable and capapble of being recycled over and over again. All reclaimed aluminum, including tin foil, can be manufactured using just 5% of the original energy consumption needed to extract the metal from the ore. As a consequence, countless tons of aluminum can be recycled on a daily basis. This not only provides ecomomic advantages, but helps preserve the environment at the same time.
Aluminum ore is known as bauxite. There are several different types, and each will contain varying amounts of aluminum along with other elements. While aluminum can be found in every handful of dirt and regardless of location, heavily concentrated amounts are found in select geographic areas. Most of the bauxite used for aluminum production in the United States comes from North America, the West Indies, and Australia.
Aluminum foil is simply a solid chunk of aluminum rolled into a very thin sheet. The minimum thickness is around .00017 inches while the maximum thickness is about .00059 inches. Foil is made by literally shaving thin layers off a larger block of aluminum, much like a sculptor whittling away at rock. Therefore, all types and grades of aluminum, including foil, must be extracted from the ore, or bauxite. Explosives are first set up where a large concentration of bauxite is found. Next, the top layers of dirt and rock are removed. Front-end loaders then place the exposed ore into trucks and railroad cars, which transport it to a processing facility. During this step, the bauxite is refined by first removing any impurities. Once this has been done, this results in aluminum oxide. In the next step, the aluminum oxide is smelted into pure metallic aluminum. This is a rather complex process that involves electrical currents and melting furnaces. In the end, stock sheets of aluminum are produced in varying thicknesses and widths.
In regard to making foil in particular, the aluminum stock is further reduced in thickness. This is done by means of a rolling mill, which literally squeezes the aluminum into progressively thinner sheets. During this process, the foil must be heat-treated numerous times to maintain its structural integrity. Different patterns can be made depending on how the product is trimmed. Similar to rolls of paper used for making newspapers, a web can break, and when this happens, it must be spliced back together. The finished product, or roll of tin foil, is then coated with any number of chemicals, resins, or polymers for decorative, protective, or heat-shielding purposes, depending on its intended use. Finally, before that roll of aluminum foil is packaged and sent to your local supermarket, it must pass inspection through quality control.
Aluminum foil is something that practically everyone now takes for granted. Still, perhaps the next time you wrap that leftover pizza up in a sheet of this versatile material, you'll appreciate it even more.