Separate Recovery of Iron and Phosphorus from BOF Slags by Using Fe-Si Alloys

Abstract

The recovery of iron from BOF slags by reduction is one of the most effective ways of its utilization. However, phosphorus which is simultaneously reduced dissolves in liquid iron almost completely.
The present work was undertaken to seek the possibility of the separate recovery of iron and phosphorus from BOF slags.
The experiments were carried out using a plasma furnace under the conditions that BOF slags were reduced by carbon powder in coexistance of Fe-Si alloy bath where silicon presumably enhances the activity of phosphorus.
More than 95% of iron and phosphorus were removed from the slags. While iron was recovered by Fe-Si alloy, the substantial amount of reduced phosphorus was removed to gas phase as P₂ gas. It is likely to be CO gas explosively generated on the reduction of iron oxide in slag that has great effect on the gaseous dephosphorization.