Steel making environmental facts

Overview of Key Environmental and Energy Facts Steel Making... 

Modern steel-making is characterized by two difTerent material flows. In one of them raw iron (pig iron) is made from iron ore and then used to manufacture raw steel. In the other technique raw steel is made by melting scrap. As a matter of fact, steel scrap is an important raw material for steel-making. UtiHzing scrap is also an important component in modern environmental thinking and in the efforts currently being made to re-use industrial products, see Figure 8.22. 

Iron comprises approximately 4.7% of the Earth s crust. The enormous quantities of this metal in the earth core are prerequisite for the magnetic field that shields the planet from cosmic radiation and enables life. The ubiquitous availability of iron and its ability to adjust its oxidation state, redox potential and electron spin state makes it suited to participate in a large number of chemical reactions. Thus, iron has become essential for animals, plants, fungi and most bacteria, ivhere it functions in a ivide variety of iron-dependent enzymes and metal proteins. To avoid deficiency symptoms, mechanisms have evolved in these organisms to maintain iron homeostasis in situations of scarce supply, but also to avoid oxidative stress as mediated by Fenton chemistry ivhen supply is excessive. In industry, iron is used in over 2500 varieties of steel, each with different physical properties. In fact, annual steel production is almost as high as that of all other metals combined hence the environmental effects of iron must also be considered. 

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