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Monday, March 24, 2008

Environment friendliness of modern steel:


Environment friendliness of modern steel:

Steel is the world's most recycled material. Steel's unique magnetic properties make it an easy material to recover from the waste stream, i.e., it can be recycled. The properties of steel remain unchanged no matter how many times the steel is recycled. The electric arc furnace (EAF) method of steel production can use recycled steel exclusively.

Most steel is made via one of two basic routes: (1) Integrated (blast furnace and basic oxygen furnace); (2) Electric arc furnace (EAF).

The integrated route uses raw materials (that is, iron ore, limestone and coke) and scrap to create steel. On the other hand, the EAF method uses scrap as its principal input.

The EAF method is much easier and faster since it only requires scrap steel. Recycled steel is introduced into a furnace and re-melted along with some other additions to produce the end product.

Steel can be produced by other methods such as open hearth. However, the amount of steel produced by these methods decreases every year.

Of the steel produced recently, about 65.0% was produced via the integrated route, 32.0% via EAF and 3.0% via the open hearth and other methods.

Steel is not a single product. There are currently more than 3,500 different grades of steel with many different physical, chemical, and environmental properties. Approximately 75% of modern steels have been developed in the last 20 years. If the Eiffel Tower were to be rebuilt today the engineers would only need one-third of the amount of steel. Modern cars are built with new steels that are stronger, but up to 25% lighter than in the past.

Steel is very friendly to the environment. It is completely recyclable, possesses great durability, and, compared to other materials, requires relatively low amounts of energy to produce. Innovative lightweight steel construction (such as in automobile and rail vehicle construction) help to save energy and resources. The steel industry has made immense efforts to limit environmental pollution in the last decades. Energy consumption and carbon dioxide emissions have decreased by one-half of what they were in the 1960s. Dust emissions have been reduced by even more.

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