METHOD FOR OPERATING MELTING REDUCTION FURNACE

PROBLEM TO BE SOLVED: To reduce the time required for re-startup from the start of a re-startup to general operation in a method for operating a melting reduction furnace which includes: blowing, in order to melt and reduce a powdery metal oxide-containing raw material by use of a vertical melting reduction furnace having a packed layer of a carbon-based solid reducing material and including two stages of tuyeres composed of an upper tuyere and a lower tuyere, oxygen-enriched air which is heated using a gas generated in the vertical melting reduction furnace from the tuyeres and blowing a metal oxide-containing raw material from the upper tuyere.SOLUTION: In the method for operating the melting reduction furnace, oxygen-enriched air is blown from the upper tuyere at a higher oxygen concentration than oxygen to be blown from the lower tuyere, in a period between the restart of the blowing of air from the tuyeres and restart of the blowing of metal oxide-containing raw material after interruption of the blowing of the air and metal oxide-containing raw material to the melting reduction furnace, and the oxygen enrichment of the air blown from the upper tuyere is started earlier than the oxygen enrichment of the air blown from the lower tuyere.