Recycling of steel

Steel is one of the most recycled materials in the world, and, as of 2008, more than 83% of steel was recycled in the United States. In the United States it is the most widely recycled material; in 2000, more than 60 million metric tons were recycled.

The most commonly recycled items are containers, automobiles, appliances, and construction materials. For example, in 2008, more than 97% of structural steel and 106% of automobiles were recycled, comparing the current steel consumption for each industry with the amount of recycled steel being produced. A typical appliance is about 75% steel by weight an automobiles are about 65% steel and iron.

The steel industry has been actively recycling for more than 150 years, in large part because it is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties during the recycling process, and has drastically reduced energy and material requirements compared with refinement from iron ore. The energy saved by recycling reduces the annual energy consumption of the industry by about 75%, which is enough to power eighteen million homes for one year.

The BOS steelmaking uses between 25 and 35% recycled steel to make new steel. BOS steel usually has less residual elements in it, such as copper, nickel and molybdenum and is therefore more malleable than EAF steel so it is often used to make automotive fenders, soup cans, industrial drums or any product with a large degree of cold working. EAF steelmaking uses almost 100% recycled steel. This steel contains more residual elements that cannot be removed through the application of oxygen and lime so it is used to make structural beams, plates, reinforcing bar and other products that require little cold working. Recycling one ton of steel saves 1.100kg of iron ore, 630kg of coal, and 55kg of limestone.

Because steel beams are manufactured to standardized dimensions, there is often very little waste produced during construction, and any waste that is produced may be recycled. For a typical 2.000 square foot (200m2) two story house, a steel frame is equivalent to about six recycled cars, while a comparable wooden frame house may require as many as 40-50 trees.

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