An aluminum can is a container for packaging made primarily of aluminum (BrE aluminium). It is commonly used for foods and beverages but also for products such as oil, chemicals, and other liquids. The common 12-ounce-size can[clarification needed] weighs 15 grams when empty.
Use of aluminum in cans began in 1957. Aluminum offers greater malleability, resulting in ease of manufacture; this gave rise to the two-piece can, where all but the top of the can is simply stamped out of a single piece of aluminium, rather than laboriously constructed from two pieces of steel. A label is either printed directly on the side of the can or will be glued to the outside of the curved surface, indicating its contents.
Most aluminum cans are made of two pieces. The bottom and body are "drawn" or "drawn and ironed" from a flat plate or shallow cup. After filling, the can "end" is sealed onto the top of the can.
The advantages of aluminum over steel (tinplate) cans include;
- light weight
- competitive cost
- usage of easy-open aluminum ends: no need for a can opener
- clean appearance
- aluminum does not rust
Aluminum cans are often made with recycled aluminum; approximately 68% of a standard North American can is recycled aluminum. In 2012, 92% of the aluminium beverage cans sold in Switzerland were recycled. Cans are the most recycled beverage container, at a rate of 69% worldwide.
One issue is that the top of the can is made from a blend of aluminum and magnesium to increase its strength. When the can is melted for recycling, the mixture is unsuitable for either the top or the bottom/side. Instead of mixing recycled metal with more aluminum (to soften it) or magnesium (to harden it), a new approach uses annealing to produce an alloy that works for both.
Notes and references
- Soroka, W. Illustrated Glossary of Packaging Terminology (Second ed.). Institute of Packaging Professionals.
- Petroleum week, Volume 9, 1959, p. 82 (Google Books)
- http://www.bafu.admin.ch/dokumentation/medieninformation/00962/index.html?lang=fr&msg-id=50084 (page visited on 4 November 2013).
- PE America: Life Cycle Impact Assessment of Aluminum Beverage Cans. Final Report: 21 May 2010.
- Wald, Matthew L. "Toward a Greener Soda Can - NYTimes.com". Green.blogs.nytimes.com. Retrieved 2012-06-13.
- Soroka, W, "Fundamentals of Packaging Technology", IoPP, 2002, ISBN 1-930268-25-4
- Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009, ISBN 978-0-470-08704-6