Patent ID: 6511629
Filing Date: 2003-01-28
Classification: C21B,F27B

Abstract:
A shaft furnace for direct reduction of a charge comprised of a material of at least one of particulate iron and sponge iron, the charge having a characteristic angle of repose when loaded in the shaft furnace, the furnace comprising:a substantially cylindrical body having an upper end into which the charge is fed, an interior in which the reduction takes place, and a bottom end at which the charge is withdrawn after reduction; a plurality of gas inlet orifices disposed around the furnace body, the gas inlet orifices being located below the upper end of the furnace body and above the bottom end thereof and communicating with the interior of the body to permit delivery of a reducing gas thereto; an annular space around the furnace to which the gas may be supplied, the annular space being connected to the gas inlet orifices by respective gas supply ducts; the interior of the furnace body including a region thereof below the gas inlet orifices, that is widened diametrally, the widened region being so shaped that it forms an annular cavity surrounding the gas inlet orifices which is substantially free of charge when the furnace is in operation, the diametral widening being in the shape of a frustoconical surface having a generatrix which forms an angle with the horizontal which is smaller than the angle of repose of the charge material.