| 摘要 |
Provided is a molten iron pre-treatment method in which, using one converter-type refining furnace, a desiliconization treatment and dephosphorization treatment for molten iron tapped from a blast furnace are consecutively carried out, wherein desiliconization treatment and dephosphorization treatment are efficiently performed even if it was difficult to accurately ascertain the state of the mass and composition of slag remaining in a furnace. Molten iron is pretreated by performing, using one converter-type refining furnace 1, the following in the order given: a desiliconization treatment step for a molten iron 5; an intermediate deposit discharge step for discharging desiliconized slag 6 generated in the desiliconization treatment step; a dephosphorization treatment step in which a molten iron 5A which is caused to remain inside of the refining furnace is subjected to dephosphorization treatment; and a tapping step for tapping a molten iron 5B that was subjected to the dephosphorization treatment. Following the tapping step, whether or not to discharge dephosphorized slag 7 generated in the dephosphorization treatment step to the outside of the furnace is determined on the basis of a phosphor content analysis value of the molten iron 5B following dephosphorization treatment of a charge. Subsequently, the molten iron of a next charge is charged into the refining furnace and the pre-treatment is carried out. |
