| 摘要 |
PROBLEM TO BE SOLVED: To efficiently perform desulfurization treatment without complicated remodeling of equipment when molten pig iron is desulfurized using a mechanical agitation type desulfurization facility using an impeller.SOLUTION: Molten pig iron stored in a cupola pot is desulfurized using a mechanical agitation type desulfurization facility equipped with an impeller. Fine granular CaO-containing material whose maximum grain size is adjusted to 5 mm or less is used as a desulfurizing agent. The desulfurizing agent is added onto molten pig iron through a pipe for dropping and adding the desulfurizing agent from a hopper storing the desulfurizing agent onto the molten pig iron or through a nozzle transferring and adding the desulfurizing agent from a tank storing the desulfurizing agent onto the molten pig iron during rotational agitation of the molten pig iron by rotation of the impeller, while the amount U of added desulfurizing agent per unit area time, specified by formula (1): U=W/t/S, is controlled to be not more than 20 kg/min/cm, wherein U is the amount of added desulfurizing agent per unit area time [kg/min/cm]; W is the amount of added desulfurizing agent [kg]; t is addition time of a desulfurizing agent [min]; and S is an area of adding a desulfurizing agent (the sum total of outlet hole areas, located above molten pig iron, of a pipe or nozzle for adding a desulfurizing agent) [cm]. |
