| 摘要 |
PURPOSE:To evaporate and dephosphorize slag to prevent the rephosphorization thereof and to make possible the production of a low-phosphorus steel by adding a reducing agent for phosphorus oxide onto the slag in a vessel such as ladle without discharging the slag therefrom and subjecting the molten steel to a pressure reduction treatment. CONSTITUTION:The molten steel which is produced in a pure oxygen converter, etc. and is not yet deoxidized or is slightly deoxided is subjected to the pressure reduction treatment in the ladle 4 of a ladle pressure reducing and refining device 7. The reducing agent for phosphorus oxide consisting of C, CaCl2, Al, etc. is added from above or injected from a lance 5 onto the slag formed in the stage of the above-mentioned production or the slag formed by a dephosphorization treatment without discharging the same, then the slag is heated by preferably plasma heating, arc heating, burner heating 6, etc. The slag is thereby efficiently evaporated and dephosphorized without rephosphorizing the same into the molten steel and the low-phosphorus steel is obtd. |
