Method for treating alloyed carbonic iron smelts used for the production of steel

Abstract

In a method of treating alloyed carbon-containing iron melts for the production of steel, whereby a carbon-containing iron melt is subjected in a metallurgical vessel to a decarburization by addition of oxygen and a part of the metallic alloying elements is slagged, whereby the metal melt is withdrawn from the metallurgical vessel while the unreduced slag remains in the metallurgical vessel and then the metallurgical vessel is filled with a new charge or iron melt and subjected anew to a decarburization process so that the loss of expensive metallic alloying elements as a result of decarburization is small because of the slagging. This is achieved in that without intervening removal of the slag, the slag is increasingly, saturated with metal oxides which derive from the melt and such that with increasing saturation the slagging of the metallic alloying elements is increasingly counteracted.

1 . A method of treating alloyed carbon-containing-iron melts for the production of steel, whereby in a metallurgical vessel, a carbon-containing iron melt is subjected to a decarburization reaction by the addition of oxygen and a part of the metallic alloying elements are slagged, whereby the metal melt is withdrawn from the metallurgical vessel while the slag remains unreduced in the metallurgical vessel and then the metallurgical vessel is filled with a new charge of the iron melt and subjected anew to a decarburization process, characterized in that without intermediate slag removal, the slag is increasingly saturated with metal oxides which derive from a plurality of melts subjected one after the other to decarburization processes and which increasingly counteracts a slagging of the metallic alloying elements.  
     
     
         2 . The method according to  claim 1  characterized in that at least 3 to 4 decarburization processes are carried out in succession.  
     
     
         3 . The method according to  claim 1  characterized in that after the saturation level of the slag is reached or the slag reaches approximately the saturation level, the slag is reduced and only then is slag removed.  
     
     
         4 . The method according to  claim 1  characterized in that during the decarburization processes the slag is strongly mixed with the melt.  
     
     
         5 . The method according to  claim 1  characterized in that with a chromium-containing steel melt, the slag is increasingly saturated with chromium oxide which results during the decarburization processes from the incomplete reduction of chromium by carbon and after reaching a saturation level or approximately a saturation level, the slag is reduced with a reducing agent for chromium oxide, especially FeSi and then the reduced slag is tapped off.  
     
     
         6 . The method according to  claim 5  characterized in that as a result of reduction of chromium oxide in the slag with carbon in the melt bath, a strong agitation of the melt bath results.