Industrial electric heating furnaces – Arc furnace device – Charging or discharging
Patent
1996-08-26
1998-02-03
Hoang, Tu B.
Industrial electric heating furnaces
Arc furnace device
Charging or discharging
373115, 373 73, 75414, 75 1061, 266 45, F27D 300
Patent
active
057152721
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a device for charging an electric furnace with a molten metal.
A large part of the recycling of scrap iron is achieved using electric furnaces such as arc furnaces. These furnaces make it possible to melt and reuse the scrap iron treated in this way in order to make new steel products such as girders, etc.
Some of the residual elements contained in the scrap iron, such as copper, nickel, etc., cannot be separated from the steel and are therefore present in the finished products. The more the scrap iron has been subjected to recycling operations, the higher will be the concentration of these residual elements. The latter are a nuisance in the manufacture of certain products such as steel sheets, etc.
One way of reducing the concentration of residual elements in the steel obtained from scrap iron is to add some liquid iron directly to the electric furnace. This method necessitates the removal of the cover of the electric furnace. It is therefore necessary to interrupt the process of melting the scrap iron, to move the cover and to pour the liquid iron into the electric furnace over the partially melted scrap iron. During this operation, large quantities of dust are released into the atmosphere and part of the iron or the partially melted steel is ejected from the furnace. Furthermore, the impact of the liquid iron risks damaging the cooling panels lining the inside of the furnace. It is clear that this method is insalubrious, dangerous and reduces the productivity of the furnace.
SUMMARY OF THE INVENTION
The aim of the present invention is to put forward a device avoiding to damage the furnace by projections of cast iron during the introduction of liquid cast iron and to minimize the loss of heat.
According to the present invention, this aim is achieved by a charging device intended to supply liquid metal to an electric furnace with a hearth, said device comprising a balcony extending the furnace hearth laterally said balcony being covered internally with a coating of a refractory material.
The device is characterized by a cover, equipped with a refractory coating, located above said balcony, said cover forming in an open position a protection shield for a part of the furnace (10) adjacent to the said device.
In the charging device according to the invention, the iron is no longer poured directly into the shaft of the electric furnace (e.g. from a ladle), but is introduced by a projecting lateral balcony communicating with the hearth of the electric furnace. There is consequently no longer any need to remove the furnace cover and interrupt the process of melting the scrap iron during the introduction of the molten metal. The productivity of the furnace is increased since the charging with iron is carried out while the plant is running. The working life of the cooling panels in the furnace shaft is increased since the iron is no longer thrown against these panels during the charging.
Moreover, emissions of dust into the atmosphere are limited since the liquid iron comes into contact with the scrap iron below the cover of the electric furnace. Consequently, the dust that is created is sucked away and dealt with by the furnace filtration system.
In addition, the refining of the molten metal may be initiated by the injection of oxygen from the beginning of the production cycle.
The inner surface of the said balcony is entirely covered by a refractory material in order to protect the balcony against the heat from the liquid iron. Preferably, the bottom of the balcony is faced with an impact plate made of a special refractory in order to prevent its premature wear.
It will also be appreciated that the supply balcony incorporates a cover fitted with a lining made of a refractory material which minimises heat losses and which forms a protective shield for a part of the furnace adjacent to the said device when it is open. In this way, the furnace is protected against ejections of liquid iron during the charging.
Preferably, the lateral supply balcony will be po
REFERENCES:
patent: 3674903 (1972-07-01), Bintzer
patent: 5153894 (1992-10-01), Ehle et al.
patent: 5238484 (1993-08-01), Pirklbauer et al.
Devillet Serge
Fries Daniel
Kaell Norbert
Hoang Tu B.
Paul Wurth S.A.
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