TECHNOLOGICAL PRINCIPLES BEHIND MAKING THE HEATING OF STEELMAKING BATHS MORE EFFICIENT AND REDUCING POLLUTION

Improving the efficiency of the heating of the steelmaking bath throug h the use of oxygen while reducing pollution remains one of the most d ifficult but important problems in the science and practice of metallu rgy. Of the different high-productivity steelmaking methods now used, the oxygen-converter method is the leading technology: the unit consum ption of oxygen averages 65 m(3)/ton in oxygen-converter steelmaking, 30 m(3)/ton in electric steelmaking, 60 m(3)/ton in open-hearth practi ce, and 70 m(3)/ton in two-bath furnace steelmaking. Most of the oxyge n is consumed in refining processes. The use of oxygen to improve ther mal efficiency is limited. Oxygen-based steelmaking methods are charac terized by low thermal efficiency, oxidation loss of metal in the char ge, wear of refractories, and emissions of dust and products of incomp lete combustion. An increase in the concentration of oxygen in the fur nace chamber increases the rate of oxidative processes (combustion of carbon, iron, and other components of the melt) but reduces fuel consu mption and increases the consumption of pig iron (heat-carrier prepare d 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.