Sms Schloemann-siemag Aktiengesellschaft

Outotec Oyj

Sms Siemag Aktiengesellschaft

Man Gutehoffsnungshutte Aktiengesellschaft

Karl-Josef Schneider

Wei-Ping Wu

Karl-Heinz Deppner

Heinz Eichberger

Andreas Hubers

In a method of charging fine-grained metals, in particular directly reduced iron (DRI), into an electric-arc furnace (), the metal is supplied via a downpipe () to an opening () provided in the furnace roof (), is introduced into the furnace () through this opening () as bulk material stream (), and falls onto the melt () merely by gravity. Further, an electric-arc furnace () suited for this purpose is described. A rather loss-free introduction even of fine-grained material having a mean grain size of less than 1 mm is achieved by passing the bulk material stream () through a dosing orifice () after the downpipe () and before entering the furnace (). The bulk material stream () then enters the furnace essentially undisturbed.

Method of charging fine-grained metals into an electric-arc furnace

An apparatus for producing steels with predominantly high Cr content and/or ferro-alloys, wherein the metal charge is melted in a melting crucible, is alloyed, refined and reduced, and wherein process gases are simultaneously supplied through bottom nozzles. A melting crucible is used with a specific reaction volume of 0.4 to 1.5 m /t steel and the injection rates of the process gases are controlled in the range of 0.1 to 3.0 N m /t/min. The solid charge material is melted by an electric arc and air/nitrogen are injected simultaneously and, after forming a liquid sump, a gas mixture of oxygen and inert gas is injected. After adding slag-forming constituents and alloying agents, the oxygen throughput is increased and the power of the electric arc is reduced accordingly. The oxygen throughput is reduced in relation to the inert gas during refining and decarburization takes place as a result of increasing the electric arc with low chromium slag formation. During the reduction of the melt with suitable reduction agents, primarily chromium is reduced from the slag and silicon is bound by slag-forming constituents.

Method and apparatus for producing high chromium content steels and/or ferroalloys in an electric arc converter

A method and an apparatus for producing steels with predominantly high Cr content and/or ferro-alloys, wherein the metal charge is melted in a melting crucible, is alloyed, refined and reduced, and wherein process gases are simultaneously supplied through bottom nozzles. A melting crucible is used with a specific reaction volume of 0.4 to 1.5 m.sup.3 /t steel and the injection rates of the process gases are controlled in the range of 0.1 to 3.0 N m.sup.3 /t/min. The solid charge material is melted by an electric arc and air/nitrogen are injected simultaneously and, after forming a liquid sump, a gas mixture of oxygen and inert gas is injected. After adding slag-forming constituents and alloying agents, the oxygen throughput is increased and the power of the electric arc is reduced accordingly. The oxygen throughput is reduced in relation to the inert gas during refining and decarburization takes place as a result of increasing the electric arc with low chromium slag formation. During the reduction of the melt with suitable reduction agents, primarily chromium is reduced from the slag and silicon is bound by slag-forming constituents.

Method and apparatus for producing high chromium content steels and/ or

An arrangement for operating an arc furnace with two vessels for making steel. Enough liquid raw iron is added to account for 70% of the total starting metallurgicals. The supply of electricity to one of the vessels is discontinued but not to the other vessel. The injection of oxygen through a lance accompanied by the addition of sponge or coolant and lime, is carried out in one vessel while an electric-arc furnace phase is carried out in the other vessel, whereby additional sponge or coolant is melted with less oxygen and additional lime or coal is added. Electrodes are mounted on an arm and can be pivoted over either vessel as desired.

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Schermbeck, Germany

Karl-Josef Schneider