Nippon Steel Corporation

Tetsuya Oh-hara

Kazushige Umezawa

Tatsuro Kuwabara

Kousaku Ozawa

Tsuzuru Nuibe

A method of melting an iron-containing cold material and simultaneously obtaining a low phosphorous and high carbon molten iron while maintaining a high post combustion rate, comprising the steps of: preparing a converter having a lance for top-blowing oxygen, and a bottom-blowing triple pipe nozzle disposed at a bottom of the converter which nozzle is provided with an inner pipe, an intermediate pipe and an outer pipe; supplying the iron-containing cold material into the converter in which a hot heel exists; introducing into the converter all of a carbonaceous material together with a non-oxidizing gas through the inner pipe of the triple pipe nozzle, oxygen through a space defined between the inner pipe and the intermediate pipe, and a non-oxidizing cooling gas through another space defined between the intermediate pipe and the outer pipe, and additional oxygen through the oxygen top-blowing lance so that the cold material is melted into a molten iron under an existence of slag; maintaining both the content of carbon dissolved in the molten iron at a level of 3 to 4% in most of a period of time for the melting and the rate of bottom-blown oxygen in a range of not less than 10% but less than 20% of the total amount of the oxygen; and adding intermittently or successively iron oxide into the slag in most of a melting period of time while keeping a slag basicity defined by CaO/SiO.sub.2 in a range of 1.5 to 3.0.

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Himeji, Japan

Tetsuya Oh-hara