Use of Preheated Air during the Ignition of a Sintering Charge.

Under conditions of a constant temperature-heat level of the process of external heating of charge layer each percent of increase in the oxygen content in the hearth gases during the combustion of natural gas, coke oven gas or blast furnace gas requires an increase in the air preheating temperature amounting to an average of 120 to 140 degree C. An increase in the air preheating temperature for each 100 degree C in the range from 0 to 600 degree C ensures a decrease in the consumption of coke oven gas and natural gas amounting to an average of 6% and a decrease in the consumption of blast furnace gas amounting to an average of 3. 5%. The use in the ignition hearth of air preheated to 300 degree C makes it possible, as a result of recovery of heat from the finished sinter, to increase the oxygen content in the hearth gases by 2% and to reduce the consumption of natural gas or coke oven gas by approximately 17%, and that of blast furnace gas by approximately 6. 6%.