METHOD FOR DEPHOSPHORIZATION OF HOT METAL

摘要

A method for dephosphorization of a hot metal, which comprises using a hot metal pretreatment vessel having a top injection lance and a bottom injection tuyere provided at the bottom thereof, and injecting an oxygen gas from the top injection lance and simultaneously injecting a gas for agitation from the bottom injection tuyere, wherein after the addition of a dephosphorization agent into the above hot metal pretreatment vessel, the injection of the oxygen gas from the top injection lance to the surface of a molten metal is carried out in the state of soft blowing until the completion of the transfer of the dephosphorization agent into a slag and is carried out in the state of hard blowing after the completion of the transfer of the dephosphorization agent into a slag, and wherein when the slag formed during the above soft blowing has an FeO content of 30 mass % or more, the flow rate of a gas for agitation from the above bottom injection tuyere is increased, to enhance the agitation between the slag and the metal.