Manganese Partition Equilibrium in Less Slag Blowing at BOF Linked to High Speed Dephosphorization of Hot Metal

Abstract

In Keihin Works low phosphorous hot metal has been obtained stably in large quantities, after improving operational conditions at hot metal dephosphorizing station.
Optimum conditions of less slag blowing at BOF using pretreated hot metal, were also studied, in particular, on Mn partition between slag and metal. Total process of hot metal dephosphorization and less slag blowing which contributed to cost saving was established.
The following results were obtained by the study of metallurgical charactarization of hot metal dephosphorization and less slag blowing.
(1) ( %T. Fe) depends on top oxygen flow rate and bottom stirring. Reduction of top oxygen flow rate and increase of bottom stirring are important for reducing (%T. Fe).
(2) Comparing slag oxygen potential with metal oxygen potential, the former is higher than the later. But its difference becomes to be small as decreasing the carbon content in metal. Mn partition ratio between slag and metal apparently depends on intermediate oxygen potential between those of slag and metal.