Recycling Steel
by Scott Sportsman
Steel recycling is beneficial on many fronts. One advantage is the reduction of the solid waste stream by recycling programs in general; another is the saving of diminishing landfill space; and a third is the savings experienced by reduced energy and natural resource requirements.
Generally, steel cans represent approximately 1.3 volume % of the landfilled Municipal Solid Waste (as of 1993) or 1.0% by weight. This is approximately 1.6 million tons of steel that will remain inert in a landfill for future generations to admire. Compounding this problem is the alarming rate at which existing landfill space is being consumed. A recent survey by the EPA found that approximately 47% of current landfill sites expect to be closed within 10 years.
Some benefits of using recycled steel instead of virgin ore to make new steel are:
| 74% 90% 86% 40% 76% 97% | Savings in Energy Savings in virgin material use Reduction in air pollution Reduction in water use Reduction in water pollution Reduction in mining wastes |
Each year, using recycled steel to produce new steel saves enough energy to electrically power about 18 million households (20% of US households) for one year! Each ton of steel recycled conserves 2,500 pounds of iron ore, 1,400 pounds of coal and 120 pounds of limestone.
Steel cans, also known as tin cans, represent the largest portion of steel consumed/recycled by the average domestic consumer. Over the past 7 years, the recycling rate for steel cans has increased from 15% to 55%. Last year this resulted in approximately 17.8 billion steel cans being re-melted, which is 566 cans every second.
Other items that are commonly collected are auto parts and farm equipment. Prior to disposal, the items should be cleaned enough to prevent nuisance odors or health hazards, and any major plastic or rubber components should be removed. Incidental amounts of contaminants, including labels, will be removed in the furnace. Common items that cannot be recycled are compressors, gas tanks and hazardous chemical drums.
Despite a common misconception, aerosol cans may be disposed of if properly emptied. Instead of simply discharging remaining contents, cans that are not empty should be returned to the manufacturer or donated to local organizations which may have a need for that product. Non-aerosol paint cans may also be disposed of when emptied. Once emptied, the lid of the can should be removed and the remaining film of paint should be allowed to dry. The re-melting process will remove the remaining layer of paint.
Unlike some other materials, the recycling process for steel is relatively inexpensive, but steel recycling is restrained by the relatively low buy-back rate of <$40 per metric ton (or slightly more than $.01/lb). The cost of recycling is relatively low because steel is easily separated and recycled due to its magnetic properties and the low level of contaminants found in the remanufacturing process.
Steel collection at CSM
Steel is collected on campus in a bin located near the paint shop and the drilling laboratory. Approximately 39 tons were collected on campus last year and disposed of through Iron & Metals, Inc., at no cost to the school. The steel was then cut into pieces smaller than 3' x 18", and sold to various steel mills.
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Contact Us At: earthworks@mines.edu
Maintained by: Bret Wilcox (bwilcox@mines.edu)
Faculty Advisor: John Humphrey (jhumphre@mines.edu)
Last Updated: July 26, 2002
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