Nippon Kokan Kabushiki Kaisha

Yotaro Oono

Hiroshi Saito

Masahiro Matsuura

Kazumasa Wakimoto

Hitoshi Kawada

Takehiko Miyamoto

Hirohisa Hotta

According to a method of operating a blast furnace, pure oxygen, pulverized coal, and a temperature control gas which substantially does not contain nitrogen are blown from tuyeres. A preheating gas which substantially does not contain nitrogen is blown from an intermediate shaft level. A blast furnace gas which substantially does not contain nitrogen can be produced from a furnace top.

Method of operating a blast furnace

A method for operating a blast furnace, comprising the steps: charging iron ores and cokes through a furnace top into the blast furnace; blowing in gas containing 40 vol. % or more oxygen together with pulverized coal through tuyeres into the blast furnance; and controlling a fuel ratio within a range of 500 to 930 kg/ton., molten pig iron and still a ratio of the pulverized coal blown in through the tuyeres within a range satisfying the formula: ##EQU1## molten pig iron, where X represents a fuel ratio. Through blown-in inlets set in the furnace shaft, preheating gas is blown in to preheat burdens. The cokes charged into the blast furnace are cokes of low strength having a drum index of DI.sub.15.sup.30 of 80 to 90% .

Method for operating a blast furnance by blowing pulverized coal

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Tokyo, Japan

Yotaro Oono