METHOD FOR OPERATING SMELTING REDUCTION FURNACE

PURPOSE:To execute smelting reduction at high yield and to reduce energy consumption by measuring each oxygen potentials of molten slag at a timing when supplying of solid raw material is stopped in a smelting reduction furnace, and at a timing after passing the optional time from the above timing and assuming the completing time of smelting. CONSTITUTION:Carbonic solid fuel is charged in the molten material in the smelting vessel 2, and by blowing oxidizing gas from the top lance 4, the solid fuel is burnt and melting of the raw material containing metallic oxide and reduction of the metallic oxide are executed. Then, the oxygen potentials Po2 , Po2 at the timing t0 after stopping supplying of the solid oxide of raw material and the timing t1 after passing the some time in the finish reduction period from the timing t0, are measured by submerging an oxygen sensor 8 in the molten slag 7. By substituting these measured values in the prescribed equation, the time tf when reaches to the preset aimed oxygen potential valve Po2* is predicted. The finish reduction time is made to suitable by completing the finish reduction operation to the predicted time tf.