The aluminium foil is well-known uses in kitchens - as food packaging to keep moisture during cooking, barbecue or package food for storage in refrigerators or freezers - this versatile material has earned other people a good reputation for interesting and innovative uses, some of which are still in use today: as wrapping paper for Easter eggs and soap bars; As a strip attached to the back of the radiator, it can reflect the heat or remove the cooking residue on the grill by retaining the heat in the heated room; As a decoration for serving food; Even like a scarecrow, the aluminum foil keeps shining in the wind.
Aluminum as a material
Aluminum, the third largest element in the earth's crust after oxygen and silicon, is extracted from a mineral called bauxite. The mineral is processed into "alumina," a pure alumina. Aluminum is then produced from alumina by passing an electric current through the alumina in a process called "electrolytic reduction.". The resulting silver metal is the basis of various alloys obtained by adding a small amount of other metals to obtain the specific properties required for various applications. Most aluminum foil packaging uses almost pure aluminum. However, alloys are increasingly "tailored" to increase strength and allow for a reduction in thickness with the same properties.
How was aluminum foil born?
Household aluminum foil is a very thin aluminum foil, ranging from about 0.006 mm to the maximum limit of 0.2 mm (200 microns) as specified in the ISO standard. It is produced from the heating of ingots (hot rolling) to the rolling of coils of thickness between 2 and 4 mm. The coil is then cold rolled to obtain a sheet of a predetermined thickness. The second method of sheet rolling, continuous casting, does not involve the ingot stage, directly transforms the molten metal into thick strip, and immediately rolls to obtain the coil which will be rolled later.
In order to get the thinnest sheet ever, two layers need to be laminated at the same time. This "double lamination" creates a difference between the two surfaces - one is matte and the other is glossy - in the double lamination process, the matte surface is inside. Then separate the two layers of aluminum foil. The resulting wide coils are divided into various widths required for further processing for the intended end use - flexible packaging, foil containers, lids, household foils, aluminum foils for heat exchangers, insulation laminates, etc.
Market data
About 75% of Europe's production (2013: over 840000 tons) is used for packaging and foil production, and 25% for technology applications. European consumers in home and professional fields use more than 120000 tons of aluminum foil for home use every year.
Protect
The main reason why barrier aluminum foil is widely used in food and beverage industry is the total barrier of light, gas and moisture. Even if it is thin, it provides perfect protection and retains the aroma and characteristics of the product. It can be used to extend the service life of delicate products and help prevent deterioration. Therefore, it can help to produce significant energy saving effect.
Mechanical properties / ductility and strength
Aluminum foil is light and strong, with unique permanent crease characteristics, making it very suitable for packaging and rewinding many different products with different shapes. When the shape of the plate is printed on it, the foil remembers its shape, especially where there are folds and edges. It is very malleable and can be easily deformed without losing its integrity as a barrier, which makes it an ideal material for home use. Shape, thickness, alloy, and temper can be selected to accurately create the characteristics required for a particular property.
Hygiene
Due to the high temperature annealing process, the aluminum foil is completely sterile once it is produced. It is safe to use in contact with food and will not host or promote the proliferation of bacteria.
High temperature performance
Aluminum foil is a kind of high thermal conductivity material. It can be heated to a very high temperature without deformation or melting, and can withstand temperatures below zero without cracking. These functions are very beneficial in a variety of family activities, from frozen storage to extreme cases of cooking in the oven and grill: no deformation, no melting, and no risk of sudden rupture. In addition, its conductivity accelerates the freezing, refrigeration and heating process of the shell and its contents, thus saving energy.
Decorative features
The metallic luster of aluminum surface and its application to all printing technologies including engraving make it possible to combine with complex design to achieve strong publicity effect. This is a very important benefit when you consider that aluminum can be easily molded and molded into attractive shapes.
Product protection and safety
Aluminum foil can be safely used in contact with food. Uncoated aluminum foil will not react with most foods. Very salty and acidic food can sometimes cause holes and discoloration. Before use, lightly smear edible oil on the aluminum foil to easily prevent holes and discoloration.
Recycling
Aluminum is completely recyclable and there will never be any loss of quality. The energy consumption of aluminum recovery process is 95% less than that of primary production, which corresponds to huge emission savings. Modern separation technology allows aluminum foil to be extracted from household waste and recycled at a fraction of the original energy cost.
If the foil is not recycled but treated in an incinerator, the laminate will oxidize and release the energy that can be recovered. In addition, the unoxidized residual aluminum can be extracted from the bottom ash of incinerator and then used for recycling.
