Patent ID: 8377169

Claim:
A method for manufacturing granular metallic iron by reducing a raw material mixture including an iron oxide-containing material and a carbonaceous reducing agent, comprising: charging the raw material mixture onto a hearth of a moving hearth-type thermal reduction furnace; reducing the iron oxide in the raw material mixture by the carbonaceous reducing agent through the application of heat, thereby forming metallic iron, subsequently melting the metallic iron, and then coalescing the molten metallic iron to granular metallic iron while separating the molten metallic iron from subgenerated slag; and cooling and solidifying the metallic iron; wherein the application of heat comprises controlling a flow velocity of an atmospheric gas in a predetermined zone of the furnace wherein the predetermined zone is a zone from a last stage of reducing the iron oxide to completion of melting the metallic iron, and wherein burners are used in the heating of the thermal reduction furnace, said burners comprising a first burner in the predetermined zone, and a second burner in a zone or zones other than the predetermined zone to which a larger quantity of gas which does not contribute to the combustion is supplied per unit time than to the first burner when the same quantity of fuel is burned in both burners.