METHOD FOR DEPHOSPHORIZATION TREATMENT OF MOLTEN IRON

PROBLEM TO BE SOLVED: To establish a technique by which the sticking and the depositing of slag on the inner wall surface in a free-board of a treating vessel are prevented so as to prevent the substantial reduction of the free-board and the accident of slopping, etc., can surely be prevented as a result, when dephosphorization in molten iron is performed by effectively utilizing converter slag as dephosphorizing agent. SOLUTION: When the dephosphorizing treatment of the molten iron is performed by utilizing the converter slag as the dephosphorizing element, at the time zone when the blowing of oxygen-containing gas is not performed, the converter slag as the dephosphorizing agent is not used, and during and after adding the converter slag, the oxygen-containing gas is blown into the molten iron from the upper part of the molten iron surface and secondary combustion is caused to raise the temperature at the free-board part and thus, the sticking and the depositing of the slag in the inner wall surface of the free-board, are prevented.