Nippon Kokan Kabushiki Kaisha

Toshin Seiko Kabushiki Kaisha

Sumifusa Iwamaru

Toshimichi Maki

Hisashi Watanabe

Mitsuya Iguchi

Takasaburo Date

A method for preheating steel scrap by an exhaust gas from a steelmaking electric furnace, which comprises: directing, when manufacturing steel from steel scrap in an electric furnace, an exhaust gas produced in said electric furnace to an exhaust gas combustion chamber provided in the middle of a discharge duct of said exhaust gas to cause combustion of carbon monoxide contained in said exhaust gas to form a combustion exhaust gas; and selectively directing part of said combustion exhaust gas into at least one scrap preheating chamber provided in the middle of a branch duct branching off from said discharge duct to preheat steel scrap charged in said scrap preheating chamber to a prescribed temperature; said method being characterized by: feeding back all of said combustion exhaust gas after preheating said steel scrap charged in said scrap preheating chamber to said exhaust gas combustion chamber to cause combustion of an incomplete-combustion gas which is produced by the incomplete combustion of combustible substances entrapped in said steel scrap and which is contained in said combustion exhaust gas.

Method for preheating steel scrap by exhaust gas from steelmaking

An apparatus for preheating steel scrap comprises: a preheating vessel, having an open top and a bottom lid capable of being opened and closed, for receiving and preheating steel scrap, said preheating vessel being adapted to receive steel scrap to be preheated from said open top and to discharge the steel scrap preheated in said preheating vessel by opening said bottom lid; a hood downwardly flaring for covering said open top of said preheating vessel, said hood being movable from said open top of said preheating vessel and adapted to introduce high-temperature waste gases discharged from a steel-refining metallurgical furnace into said preheating vessel; a pit for housing said preheating vessel, said pit being provided with a duct for discharging to the outside said waste gases discharged into said pit from the bottom of said preheating vessel after preheating said steel scrap received in said preheating vessel; and, a canopy for sealing the gap between said pit and said preheating vessel housed in said pit, the gap between the periphery of said canopy and said pit being liquid-sealed. The apparatus is characterized in that: said canopy is gas-tightly fixed to said hood; and, the gap between said canopy and said preheating vessel housed in said pit is sealed by an expansion bellows fixed at an end thereof to said canopy.

Growing community of inventors

Himeji, Japan

Sumifusa Iwamaru