DESULPHURIZATION METHOD OF SULFUR IN HOT METAL USING SLAG OF PRE-TREATING PIG IRON

A desulfurization method of hot metal using slag of preliminarily treated hot metal is provided to improve desulfurization efficiency and reduce production costs by using expensive hot metal slag generated in the preliminary hot metal treatment process as it is and creating a reductive atmosphere from a reaction atmosphere without using an additional desulfurizer when performing a correcting desulfurization reaction. A desulfurization method of hot metal using slag of preliminarily treated hot metal comprises: a hot metal discharging step of discharging hot metal and hot metal slag into a ladle if higher than 30 ppm of sulfur is contained in hot metal that has completed a preliminary hot metal treatment; a subsidiary material injecting step of injecting an aluminum dross into the ladle to create a reductive atmosphere in which the hot metal slag contains 2 to 5% of iron oxides(T.Fe), the aluminum dross reacting with the iron oxides in the hot metal slag to remove oxygen in the iron oxides; a reaction step of agitating materials in the ladle, thereby performing a desulfurization reaction between the hot metal slag and the hot metal to obtain hot metal with a sulfur concentration of not higher than 30 ppm; a slag discharging step of discharging the hot metal slag after finishing the desulfurization reaction; and a completing step of charging desulfurized hot metal into a converter.