To provide a main iron trough of a blast furnace which obtains the long service life and can reduce the working load at the time of repairing, by restraining the development of local wearing in a refractory without drastically changing the main iron trough equipment of the blast furnace.
An angle of the surface of tip part of a projecting part shifting from both inside side wall just below the molten iron dropping position in the main iron trough of the blast furnace to the projecting part 6 to the side wall surface, is made to ≤12° and an angle of the tangential line at the highest position of the projecting part to the side wall surface is made to ≤12°. The projecting part 6 is arranged so that the length (a) from the tip part of the projecting part to the highest position of the projecting part 6 in the length direction of the main iron trough to the width (b) of the inside of the main iron trough is made to satisfy a/b ≤1.1.
NAKAMURA YUKIHIRO
YAMADA YOSHIHIRO
