Abstract: Through industrial test of Shougang Jingtang 300 t combinedblowing BOF semisteel process with fluorine and fluoridefree，the conditions of melting fluorinefree slag was illustrated theoretically. Compared to two kinds of slagging process by industrial test, the results show that combination with using residue, high lance position operation, slag agent addition and reduce the heating speed of bath which can obtain good effect of slagging. Fluorinefree process has been realized that reduce costs an average of 0.904 million yuan one month, expecting cut the cost to increase the profit of 10.85 million yuan one year.

Key words: BOF, fluorine free, slagging