Patent ID: 8157888
Filing Date: 2012-04-17
Classification: C21B,Y02P

Abstract:
1. A method of producing molten iron containing carbon of 3.0 mass % or more, the method comprising: feeding powdery carbonaceous material onto a hearth of a moving-hearth reducing furnace as hearth material; feeding raw material mixture containing carbonaceous reducing agent, iron oxide-containing material and first CaO-containing material onto the hearth material; heating the raw material mixture in the reducing furnace and thus reducing iron oxide in the raw material mixture and forming low melting-point complex oxide from the first CaO-containing material; generating solid reduced iron having metallization ratio of 80% or more; feeding the solid reduced iron in the state kept at high temperature, the low melting-point complex oxide and second CaO-containing material into a melting furnace and further heating the solid reduced iron therein; and reducing iron oxide partially remaining in the solid reduced iron and melting the solid reduced iron; wherein the sum of the amount of the first CaO-containing material blended in the raw material mixture and the amount of the second CaO-containing material fed into the melting furnace is adjusted such that basicity of slag generated in the melting furnace is 1.1 or more, and the amount of the second CaO-containing material fed into the melting furnace is reduced to 40 kg or less per ton of molten iron obtained in the melting furnace, and CaO-containing material needed in excess is blended previously into the raw material mixture as the first CaO-containing material, when the sum of the amount of the first CaO-containing material and the amount of the second CaO-containing material for satisfying the basicity is over 40 kg per ton of the molten iron.