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Method of operation of a D.C. electric-arc furnace with bottom electrode and refractory part for its implementation
| Details |
Inventors: Blumenfeld, Philippe; Destannes, Philippe; Lebrun, Christian;
Assignee: Clecim (Societe anonyme) (Cergy-Pontoise cedex, FR)
Primary Examiner: Hoang; Tu
Assistant Examiner:
Attorney, Agent or Firm: Sixbey, Friedman, Leedom & Ferguson
The method relates to the operation of a D.C. electric-arc furnace provided with at least one bottom electrode including an elongated metal current-supply body passing through the hearth of the furnace and surrounded by a casing made of dense refractory substance, comprising at least one shell ring whose upper end comes into contact with the molten metal in the furnace. During restarting of the furnace after shut-downs, a free expendable annular part made of refractory material, of flattened general shape, is placed on the upper end of the shell ring, which part extends it upwards and is intended to come into contact with the molten metal instead of said shell ring. The method applies in particular to D.C. electric-arc furnaces for the manufacture of steel, and is intended to reduce wear on the refractory parts surrounding the bottom electrode. |
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DETAILED DESCRIPTION The object of the invention is to limit or even prevent wear on the upper shell ring, in order to extend the lifetime of the shell rings and of the hearth in its entirety, and to reduce the operational shut-downs and the costs incurred due to complete reconstruction of the hearth.
With these purposes in mind, the object of the invention is a method of operation of a D.
C.
electric-arc furnace, through the hearth of which passes at least one cooled bottom electrode comprising an elongated metal current-supply body, surrounded in that part of it which passes through the hearth by a casing of dense refractory substance emerging at the surface of the hearth and consisting of at least one shell ring, in which method, during restarting of the furnace after shut-downs, a free expendable annular part made of dense refractory substance is placed on the upper end of said shell ring, which part extends it upwards in order to come into contact with the molten metal in the furnace instead of said shell ring.
As can be seen, the invention therefore consists in making the upper end of the refractory casing surrounding the bottom electrode and intended to come into contact with the molten metal in the furnace in the form of a free expendable refractory component which is easy to replace, because it is simply placed on the bottom of the furnace.
Thus, a further object of the invention is such a component as defined in the claims hereinbelow, as well as entire refractory casing comprising this component.
By virtue of the invention, it was possible to observe a marked decrease in the rate of wear.
This rate, which is of the order of 0.
5 mm thickness reduction of the hearth around the electrode per casting, on average, according to the prior art, drops to only 0.
2 mm per casting when employing the method according to the invention.
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I/O Systems 
