Abstract: A process for melting a ferrous burden comprising scrap iron, scrap steel, pig iron, direct reduced iron or mixtures thereof without the use of coke is provided. Air or enriched air as a primary oxidant is preheated and together with fuel is combusted to form a reducing atmosphere in a shaft furnace or forehearth which melts the ferrous burden in the melting zone of the shaft furnace. The reducing atmosphere leaving the melting zone of the shaft furnace is further combusted with a secondary oxidant in the preheating zone of the shaft furnace. The top gas from the preheating zone of the shaft furnace is combusted with a tertiary oxidant to provide a heated flue gas to preheat the primary oxidant. Optionally, the heat remaining in the flue gas after preheating the primary oxidant may be recovered in a waste heat recovery device.
Abstract: A recuperative burner having a recirculating conduit to direct flue gas to the combustion chamber with the air and fuel, and a compact recuperative stack with a recuperative flue gas conduit and an air passage in which air separated from the flue gas by the recuperative flue gas conduit is preheated before supplying it to the combustion chamber.