REGULATING METHOD FOR COOLING GAS IN MANUFACTURE OF REDUCED IRON

摘要

PURPOSE:To prevent precipitation of carbon and reoxidation at the time of cooling iron ores by reforming exhaust gas from a reduction furnace with a neutral gas or steam to control the CO2 and CO contents and utilizing the reformed gas as a cooling gas. CONSTITUTION:Top exhaust gas from shaft reduction furnace 1 is passed through dust collector 3 and CO converter 4 to lower the CO concn. with a neutral gas or a CO free non-oxidizing gas, or the exhaust gas is reacted in the presence of steam to convert CO into CO2 and H2. The exhaust gas is then intruduced into CO2 removal unit 5 to carry out CO2 removal. By the treatment the compsn. of the exhaust gas is reformed as follows; CO2; 5-20vol% and CO up to 30vol% or up to 15vol% when H2 up to 1vol% or not less than 1vol%, respectively. The reformed gas is supplied to cooling zone 2 of furnace 1 to cool reduced pellets. By this method no trouble due to precipitation of carbon in the reduced pellets occurs and a decrease in product value due to reoxidation is prevented.