Nippon Kokan Kabushiki Kaisha

Toshin Seiko Kabushiki Kaisha

Himeji Tekko Refine Co., Ltd.

Kazuharu Yatsunami

Akira Honda

Satoru Miyakado

Katsuaki Shiohara

Noboru Sakamoto

Tsuneo Miyashita

Seiji Matsui

Hisashi Watanabe

Yoshiro Suzawa

Tsuneo Kataoka

In a method of producing unbaked agglomerates, green pellets or briquettes are produced by adding 5 to 30% of reduced iron powder, mill scale powder or iron sand and also adding a binder consisting of a cement or granulated blast furnace slag and then the green pellets or briquettes are dry cured thereby producing agglomerates having excellent reducing performance.

Method of producing unbaked agglomerates

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

In the production of reduced pellets such as reduced iron pellets by the grate-kiln system for firing, a distributor and a belt conveyor provided with a weighing machine are arranged between a sieving machine that sieves produced green pellets to predetermined grain sizes and a travelling grate of a pretreatment furnace. The weight of green pellets fed from said sieving machine through said distributor onto said belt conveyor is continuously measured on said belt conveyor by means of said weighing machine, and a signal indicative of the measured value is fed back to said distributor. Said distributor operates in response to said signal and regulates the supply of green pellets so that the supply of green pellets to said belt conveyor, hence the supply of green pellets to said grate is kept constant. Said distributor is of such a construction as will not crush green pellets.

Method of feedig green pellets onto grate of pretreatment furnace in the

In the production of reduced iron pellets from a material mainly comprising dust exhausted from metallurgical furnaces for iron and steel production, such as blast furnaces, converters, hearth furnaces and electric furnaces, and/or a mixture thereof, by means of a grate-kiln a furnace including a pretreatment furnace comprising, a drying zone, a preheating zone a hardening zone and travelling grate passing sequentially through said zones, and a rotary kiln receiving the output pellets from the hardening zone, hot exhaust gases from the rotary kiln are first passed through said hardening zone and then through said preheating zone to harden and preheat green pellets moving therein. Said exhaust gases are then introduced into a first dust collector, where dust of a high zinc content is almost completely collected from said exhaust gases. Said exhaust gases so purified are then passed through said drying zone to dry green pellets moving therein. Said exhaust gases are then introduced into a second dust collector, where dust is further collected from said exhaust gases before said exhaust gases are discharged out of a stack to open air. When the temperature of said exhaust gases which have passed said first dust collector is not high enough for a heat source for drying green pellets moving in said drying zone, the temperature of gases for drying is raised by blowing hot gases, which are separately produced by a fuel burner, into said drying zone. The dust of a high zinc content collected by said first dust collector is used as a material for zinc refining.

Method for the collection of dust of a high zinc content during the

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Nishiohimachi, Japan

Kazuharu Yatsunami