Patent ID: 8747518
Filing Date: 2014-06-10
Classification: C21C

Abstract:
1. A method for producing foamed slag on a stainless steel melt in an AOD (argon oxygen decarburization) or MRP (metallurgical refining process) converter for stainless steel by adding a foaming material, wherein a mixture ( 5 ) of a metal oxide, iron carrier, carbon, and binding material is introduced into the converter as pellets or briquettes ( 4 ) and reacts in a chemically reducing manner under a slag layer ( 2 ) due to a high ambient temperature, wherein gaseous carbon monoxide, which is formed by a process of reducing the metal oxide with the carbon inside the pellets or briquettes ( 4 ), produces the slag foaming with its gas bubbles ( 7 ), wherein the addition of the foaming material is carried out in such a way, by specific control with values of 2-30 kg of pellets or briquettes ( 4 ) per metric ton of metal melt ( 1 ) per minute, that a well-defined foamed slag height is obtained and then maintained for a predetermined period of time, and that the charging of the foaming material is distributed in layers and in such a way that the entire area is covered with a well-defined weight per unit area that amounts to 1-5 kg/m 2 /min for an optimal foaming effect.