Dephosphorization Test of Cr-containing Molten Iron by CaO-based Flux

Dephosphorization tests of Cr-containing molten iron by CaO-based flux have been carried out by a induction furnace. The following results were obtained:1) When the carbon content in metal was enough high, Cr-containing molten iron was able to be dephosphorized by CaO-CaF2-FeO flux. In this case, oxygen partial pressure at slag and metal interface was calculated as about 10-12Pa.2) The higher ratio of CaF2/(CaO+CaF2) and of CaO/O in flux were effective for the dephosphorization without the oxidization of Cr.Based on these results, 200ton scale industrial tests have been carried out by the hot metal pretreatment station at Yawata Works. By the combination of the flux injection method and the oxygen top blowing method, it was clarified that the dephosphorization without Cr oxidation and the suppression of temperature drop were able to be achieved simultaneously.