Steelmaking - Technological options

During the last 125 years, the steel industry has witnessed revolutionary changes in the process of steelmaking. The Bessemer process was the predominant steel production technology during the last two decades of the 19th century. The open hearth process accounted for the lion's share of world steel production for six decades from 1910 to 1970. With the appearance of the LD process on the industrial stage in 1952, the importance of open hearth process declined and currently the basic oxygen processes are contributing more than 60 per cent of the world steel production. The LD process also led to the development of several other oxygen blown processes such as LDAC, OLP, OEM, QBOP, EDF, etc. The electric are furnace process of steelmaking has been in commercial use since 1910. Its share in the world steel production has been increasing steadily and today, it accounts for almost 33 per cent of the world crude steel production. The main advantages of the electric are furnace are its flexibility of unit size; capability of producing all grades of steel: and lower investment. Generally speaking, the process has been utilising scrap as feed material which leads to the problem of residual impurities in the product. With the advent of the DR processes and the availability of feedstock of known characteristics, however, the dependence on steel scrap has been reduced to some extent. From the economic viewpoint, the availability and cost of the electric power are the decisive factors governing the application of the electric are furnace process. The recent technological developments in steelmaking are primarily centred around reducing the energy consumption; utilising virgin metallic iron in different forms as metallic charge; and lowering the tap to tap rime to synchronise with continuous casting operation. There are several technological options available today for steelmaking through the electric furnace route. It is expected that by the year 2010, the contribution of electric furnace to world crude steel output would increase to about 40 per cent.