Nippon Kokan Kabushiki Kaisha

Toshin Seiko Kabushiki Kaisha

Himeji Tekko Refine Co., Ltd.

Hisashi Watanabe

Toshimichi Maki

Mitsuya Iguchi

Takasaburo Date

Sumifusa Iwamaru

Kazuharu Yatsunami

Yoshiro Suzawa

In a method for recovering zinc and lead from a dust containing ferric oxide, zinc oxide and lead oxide discharged from a metal refining metallurgical furnace, the dust is charged into the entry of a rotary kiln together with a granular carbonaceous reducing agent. The atmosphere of the interior of the kiln comprises a reducing atmosphere zone accounting for a major portion of the interior including the entry section of the kiln and an oxidizing atmosphere zone accounting for a minor portion of the interior including at least a part of the exit section of the kiln. The temperature of the interior of the kiln is increased by the combustion of a fuel from at least one burner installed at the exit section of the kiln directed toward the interior of the kiln. The dust is reduced in the reducing atmosphere zone to vaporized zinc and lead, and also to reduce the ferric oxide into ferrous oxide. The resultant zinc and lead are reoxidized in the oxidizing atmosphere zone, and discharged from the kiln, together with exhaust gases produced in the kiln to recover zinc and lead. The method includes the characterizing step of reoxidizing the ferrous oxide into the ferric oxide in the oxidizing atmosphere zone. The characterizing step has an effect enabling saving an amount of the reducing agent used as the fuel which corresponds to the amount necessary to generating the heat corresponding to that obtained by the reoxidation heat of the ferrous oxide.

Method for recovering useful metals from dust discharged from metal

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.

Apparatus for preheating a steel scrap

Growing community of inventors

Himeji, Japan

Hisashi Watanabe