Technological principles behind making the heating of steelmaking baths more efficient and reducing pollution

Improving the efficiency of the heating of the steelmaking bath through the use of oxygen while reducing pollution remains one of the most difficult but important problems in the science and practice of metallurgy. Of the different high-productivity steelmaking methods now used, the oxygen-converter method is the leading technology: the unit consumption of oxygen averages 65 m³/ton in oxygen-converter steelmaking, 30 m³/ton in electric steelmaking, 60 m³/ton in open-hearth practice, and 70 m³/ton in two-bath furnace steelmaking. Most of the oxygen is consumed in refining processes. The use of oxygen to improve thermal efficiency is limited. Oxygen-based steelmaking methods are characterized by low thermal efficiency, oxidation loss of metal in the charge, wear of refractories, and emissions of dust and products of incomplete combustion. An increase in the concentration of oxygen in the furnace chamber increases the rate of oxidative processes (combustion of carbon, iron, and other components of the melt) but reduces fuel consumption and increases the consumption of pig iron (heat-carrier prepared in the blast furnace). Attempts to use combustion air with an oxygen content higher than 25–30% in open-hearth steelmaking have shortened the life of the roof refractories and increased downtime for repairs. “TsNIIchermet” State Science Center. Translated from Metallurg, No. 9, pp. 25–28, September, 1996.