| 摘要 |
PROBLEM TO BE SOLVED: To surely enable to obtain desired [P] by regulating supplying quantities of gaseous oxygen and solid-state oxygen source and a supplying timing in a dephosphorizing treatment.SOLUTION: In the dephosphorizing treatment, the charge of dephosphorizing agent for adding from the upper part of a converter-type refining vessel is completed until the supplying quantity of the gaseous oxygen becomes 30%, and in the first blowing term, the supplying speed of the gaseous oxygen is made to be 0.9-1.2 Nm/min/t. In the second blowing term, the supplying speed of the gaseous oxygen is made to be 0.5-0.8 Nm/min/t. In the third term, the supplying speed of the gaseous oxygen is made to be 0.9-1.2 Nm/min/t. The diameter converted to the circle of the solid-state oxygen source for adding from the upper part of the converter-type refining vessel is made to be 1-10 mm. In the first charging term, the average supplying speed of the solid-state oxygen source is made to be 5-20 kg/min/t. In the second charging term, the charging supplying speed of the solid-state oxygen source is made to be 0-0.5 kg/min/t. |
