Steel containers may have originated in 14th century Bohemia. However, it wasn't until 1809 that a Frenchman invented a process to package preserved food in cans. Three years later, tin-plated cans were produced in Britain and perfected during the next four decades. And, in 1938, the steel beer can was first produced.
Steel cans are made from tinplate steel, which is produced in basic oxygen furnaces. A thin layer of tin is applied to the can's inner and outer surfaces to prevent rust and to protect food and beverage flavors. As a result, steel cans often are called “tin cans.” However, a chromium wash is replacing tin in the can-making process.
Most steel cans are used for food products (steel cans account for more than 90 percent of food cans), followed by paint, aerosols and other products. Today, more than 600 shapes, styles and sizes of containers are used.
Steel Can Municipal Solid Waste (MSW) Facts:
- 2.69 million tons or 1.2% by weight.*
- 19.92 pounds of steel cans per person.*
- 33.6 billion steel cans, or 125 per person, were used in 2000.
- The average steel can weighs 2.55 ounces.
- 1.5 million tons for a 56.1% recycling rate.*
- 19.5 billion cans for a 58.4% rate in 2000 (industry data).
- The basic oxygen furnace process uses a minimum of 25% scrap steel to make steel products including tinplate for cans. Steel cans provide less than 10% of this scrap.
- Electric arc furnaces use virtually 100% scrap steel to make products such as railroad ties.
• Steel cans do not compost. However, they are biodegradable in the sense that steel cans left exposed to the elements will slowly rust.
Incinerated or Landfilled:
- 1.2 million tons or 0.7% of discarded MSW by weight.*
- Steel cans are noncombustible.
- Waste-to-energy facilities will normally use magnets to remove steel cans before incineration.
• 4.03 million cubic yards or 1% of landfilled MSW.
- Whole, unflattened steel cans have a density of 150 pounds per cubic yard.
- Baled cans have a density of 850 pounds per cubic yard.
- Landfilled steel cans weigh 560 pounds per cubic yard.
Today's steel cans have one-third less metal than 20 years ago. In addition, during the past 25 years, average tinplate thickness has been reduced by 30%, from 0.20 mm to 0.14 mm.
Steel mills are the largest market for steel cans. Integrated mills use the basic oxygen process to manufacture tinplate, appliances, car bodies and steel framing.
Electric arc furnaces use 100% scrap to produce steel shapes such as railroad ties and bridge spans. Electric arc furnaces are more geographically diverse and tend to have smaller capacities than basic oxygen furnaces.
Detinners remove the tin from steel cans for resale to tin using industries. With less tin use in steel cans, the importance of the detinning market has substantially declined.
Foundries use scrap as a raw material in making castings and molds for industrial users.
Steel cans are covered by Institute of Scrap Recycling Industries, Washington, D.C. Ferrous Scrap Guidelines FS 213, “Steel Can Bundles.”
Cans may be baled without removal of paper labels, but must be free of other nonmetallics. Nonferrous metals and large pieces of plastic that were not eliminated at processing facilities can create safety and production problems in a steel furnace.
Recycling Cost and Value:
- Collection costs range from $217 per ton to $309 per ton.
- Processing costs range from $30.22 per ton to $125.64 per ton.
American Iron & Steel Institute, Washington, D.C. Website: www.steel.org
Can Manufacturers Institute, Washington, D.C. Website: www.cancentral.com
“Municipal Solid Waste Generation, Recycling and Disposal in the United States: Facts and Figures for 1998,” U.S. Environmental Protection Agency (EPA), Washington, D.C. Website: www.epa.gov
National Recycling Coalition, Measurement Standards and Reporting Guidelines Alexandria, Va. Website: www.nrc-recycle.org
Resource Recycling Technologies, Vesta, N.Y.
“Scrap Specifications Circular,” 1998, Institute of Scrap Recycling Industries, Washington, D.C. Website: www.isri.org
Steel Recycling Institute, Pittsburgh, Pa. Website: www.recycle-steel.org
Waste Recyclers Council, Washington, D.C. Website: www.envasns.org
*1998 U.S. EPA estimates.
Chaz Miller is director of state programs for the Environmental Industry Associations, Washington, D.C. E-mail the author at: [email protected].