Patent ID: 9315875
Filing Date: 2016-04-19
CPC Classification: C21C

Claim Text:
1. A method of refining molten iron, the method comprising: charging molten iron and a cold iron source into a converter refining vessel; supplying or charging an auxiliary material containing CaO as a main component to the converter refining vessel; supplying a first oxygen source and a first silicon-containing material or a combination of a silicon-containing material and a carbonaceous material to the converter refining vessel as a heat source to dissolve the cold iron source and conduct desiliconization of the molten iron; removing at least a part of slag produced by the desiliconization as an intermediate slag removal; and subsequently supplying a slag-forming agent and a second oxygen source to the molten iron in the converter refining vessel to conduct dephosphorization, wherein the desiliconization is carried out under conditions such that a basicity of the slag after desiliconization is in the range of 0.5 to 1.5, a molten iron temperature after the desiliconization in the range of 1280° C. to 1350° C., and not less than 30 mass % of the slag produced in the desiliconization is removed from the converter refining vessel in the intermediate slag removal.