Steel industry: A report on technology, trends and cost copetitiveness; Credit analysis and Research Limited (CARE), Bombay

Abstract

The main inputs for the iron/steel making process include iron ore. fluxes such as limestone and dolomite, coal, power, scrap/sponge iron and refractories (as consumable). The choice of inputs depends on the quality of the ore, availability, the relative cost dynamics of substitutable inputs and the quality of the finished product. Ore processing before charging to the blast furnace is important from the point of view of enriching the ore to increase the blast furnace productivity. Techniques range from simple removal of gangue matter by washing to sophisticated beneficiation techniques and agglomeration procedures such as sintering and pelletising. Steel is basically an alloy of carbon and iron with the carbon content ranging from less than 0.1% to 2.0%. In addition, some trace elements may remain as impurities. The presence of carbon and other alloying elements determines to a large extent the quality and properties of steel. Steel may be made by refining the pig iron (also adding scarp) in converters or by melting scrap and sponge iron in controlled proportion in an electric furnace to get the desired quality of steel. In the EAF technology, earlier AC EAFs were used. Now, however, DC EAF designs are also available. ‘There are significant advantages of DC EAE in terms of the power supply network system.